by Martin Bailey | Aug 10, 2009 | Podcast
Today, in the first Q&A episode for a year, I answer a question from a listener about shooting under a grey sky, and I also go into detail on why I use Manual Mode, especially in challenging exposure situations.
The question that I’m going to answer today is from Eric Vogt, from the States.
Eric wrote:
“Thanks for all your teaching and all the time you sacrifice for our hobby. I was at the beach in Oregon this past weekend where the skies were overcast. I was shooting the many pelicans there, but so many photos looked like the one attached here below. How would you approach shooting into an overcast sky?
Would you set exposure compensation to be overexposed a full stop or so? I was able to slowly get very close to these shorebirds, but was disappointed with lighting in the photos. Was it just a foul day for good photos of these birds? I’ve heard so many times that overcast days give great light, but is that just for portraits?”
Thanks very much for the great question Eric. My response is a bit long, as there’s a lot to cover here, but I’m sure you’re not the only person that has trouble with these sort of conditions, so let’s take a look at your shot and see what could have been done. The first thing I want to say is that the pelican itself is very sharp, so congratulations on your technique! I also like how you have not got the pelican dead-center, which is great.
Pelican (original) from Eric Vogt
For sure, an overcast day like this is not the most ideal for shots of birds in flight. We don’t always have the luxury of choosing the shooting conditions though, so I’ll explain what I’d bear in mind if I was shooting in these conditions.
On the exposure, you’re right. Had you used exposure compensation, this would have improved the shot greatly. I’d say you could have gone to around plus one and a third or one and a half stops, depending on how your camera is set up, and you’d have gotten the pelican perfectly exposed, and the sky would still not have been blown out.
Pelican by Eric Vogt (with +1.33 Exposure added in Lightroom)
We can also see here that I took the image into Lightroom and made a few minor adjustments to see what could have been achieved with exposure compensation. To get to the optimal exposure for this shot, I added 1.33 stops exposure in Lightroom to bring out the details in the pelican. You can also see that the sky is almost white now, which is what Eric probably saw, not quite as grey as in the original. The sky in Eric’s shot is almost a perfect grey card, which is exactly what the camera wants to do to every image you shoot. That is, turn it into an 18% grey.
Overcast skies can be great, and I personally prefer an overcast sky for many subjects, including flowers and landscapes in many situations. For this sort of bird photography though, it does pose a challenge to get nice flight shots. My suggestion if you are to shoot in conditions like this is just to get as close as possible, filling the frame with the bird and reduce the amount of sky around it. Notice also that in my version I cropped the line of trees out as well. I don’t think they add anything to the shot, and we basically want to try to compose to avoid things that don’t add anything, kind of like editing in camera.
I know that there are limitations on how close you can get, either physically, or with your longest lens. I see that Eric shot this with a 200mm focal length, and found out in follow up communication that Eric was using the 70-200mm F4 IS lens, which is a wonderful piece of glass. Eric also tells me that although he had a 1.4X Extender, which is what Canon calls a tele-converter, but he didn’t use it because he wanted to get some shots of some friends childer on the beach. This is a worthy reason to leave off the extender, but quite often, we have to make a decision on which subject to go for. If getting a good shot of the pelican is important to you, then you could drop the extender on for a while, at least until you get your shot, then take it off and go back to shooting the kids. Trying to do more than one thing in photography can often end up in you not getting your shot, or any shot at all.
Realistically though, for bird photography, even with something as big as a pelican, you need something a bit longer, even than 280mm, which is what the 70-200 would reach with the 1.4X extender fitted. Although I should note that Eric was using a Canon Rebel XT, which has a 1.6 crop factor, so Eric was actually shooting at 320mm, and that would become 450mm with a 1.4X Extender, which is pretty good and would have made for a nicely framed image of the pelican.
Ideally though, especially if you are going to shoot smaller birds, it would be nice to get something a little longer. I really enjoyed the 100-400mm lens from Canon for a number of years, especially when I was just starting out. The 100-400mm is a little on the soft side, but you can’t beat it for versatility. You could also consider something like the 150-500mm from Sigma, which would be great for birding, but it is a little dark at F5.0, going to F6.3 as you zoom to towards 500mm. Still, it’s not an incredibly expensive lens for the reach, and probably worth thinking about.
Again, in follow up communication, Eric also mentioned the 300mm f4 with the tele-converter or the 400mm f5.6 prime lenses, which shows that Eric is definitely a discerning photographer when it comes to sharpness. My advice here is that if you can handle the fact that you will miss some shots because of the inability to zoom, then for sure, these prime lenses will give you sharper images. I myself use the 300mm F2.8 sometimes with, and sometimes without the 1.4X extender, and I am getting incredibly sharp bird shots, even hand-held with this combination, but I do miss shots sometimes. I clip the wings tips off, or even just cannot get the bird in the frame as they come closer towards me sometimes.
I do of course use a second body with something like the 70-200mm F2.8 L lens sometimes as well, when I’m shooting big birds like the Red-Crowned cranes that can sometimes fly overhead, requiring a much shorter focal length to fit in the frame. I’m happy with my decisions now, and am enjoying nice sharp images, but I do sometimes miss the versatility of the 100-400mm.
My point here is that for serious bird photography, you really can’t avoid getting a long lens. I also use the 600mm F4 L Lens, and put the 1.4X extender on it when I need that extra reach. I may pick up the Sigma 300-800mm lens too, as I’m hearing a lot of good things about that lens, and the versatility, along with that reach, is something not to be sniffed at. It also has a constant aperture of F5.6, which isn’t that bad for a lens of this focal length. We are talking about a $7,000 to $8,000 lens hear though, and I realize that most people aren’t going to pay this amount for what is essentially a hobby.
Honking Dance
I’m certainly not saying that Eric needs to buy an $8,000 lens, but had he managed to fill the frame with the pelican, not only would the camera’s meter have gotten a better exposure reading, because of the darker subject filling more of the frame, it would have enabled Eric to get rid of much more of the sky. Again, if something doesn’t add to the shot, try to get rid of it. I should note though, with regards to composition, even when cropping tightly, I would still leave a little room to the right to give the impression that the pelican has some space to fly into. Rules are made to be broken of course, but in general, you want to give our subjects room to move. Putting it right up against the side that it’s moving towards can give a sense of drama, but more often than not, it just looks like bad composition.
With camera’s having more and more pixels each year, you can of course consider cropping the image in post processing, but you don’t want to throw away too many pixels, if you think you might want to print the image pretty large at some point. If you only want to use the image on the Web or view it on the computer screen though, that would be fine.
Anyway, let’s get back to the exposure discussion, as although until now I have been replying to Eric’s question about using Exposure Compensation, another thing that comes up very often is shooting in Manual mode. In Eric’s situation, shooting up at a plain grey sky, Exposure Compensation would have been fine, unless the pelican flew across a much brighter or much darker background. If that’s the case, although this can be very daunting initially, I usually recommend using the cameras Manual mode. Whenever the subject is moving from a background that is sometimes brighter, then other times much darker than the subject, it really helps to not have to think about the background at all, and the only way you can do this is to use Manual mode.
This takes a lot of getting your head around if you haven’t tried this for yourself, but if you keep in mind that your subject’s color and luminosity will not change unless the lighting conditions do, it really doesn’t matter how bright or dark the background is, if you know that you have set your camera set to expose your main subject correctly.
I’ve spoken about this many times before, but the subject comes up quite often in the forums, so let’s look at a few example shots of my own to illustrate what I’m talking about. First, let’s look at image number 2115 (above right). Now, this image would probably have only required around plus 1/3 or so of a stop Exposure compensation, because although the main subject is predominantly white, the top half of the background is very dark, so it would have balanced itself out, only requiring a little bit of compensation. I can’t tell you exactly how much compensation I used, because I shot it in Manual mode, and that doesn’t leave a record of exposure compensation, because it’s not used.
Crane Preening 2009
Imagine though, that after I shot this image, I turned and saw the crane that we see in image number 2126 (right), preening himself, with a totally white background. Using evaluative metering, which now does tend to recognize a snow scene better than it used to, I’d probably need to add around one and a third stops of exposure compensation to tell the camera that this scene is predominantly white, and that I don’t need it to darken it down. Without this compensation, the camera would have tried to make this an 18% grey, which we all know is not the color of snow. I should note that it used to be common to need up to two stops of exposure compensation for bright snow, but the newer meters in evaluative mode do seem to recognize snow scenes better than they used to, and so are a little closer, requiring only one and a third of a stop much of the time now.
This scene lasted a little while, and I could probably have thought to change the exposure compensation if I was using Aperture Priority, imagine though, as I was buried deep into my viewfinder shooting the preening crane, what if I heard a honking coming from my right, and looked up to see the pair of cranes in image number 2107 (below)? They’d just come into site, and were perfectly in line like this. I then have to think, OK, so now I’m going from a perfectly white scene, to a shot with a very dark background. I’m probably going to have to go from plus one and a third of a stop, to minus one stop, or I’ll over-expose the two birds here. I start to turn the dial, while looking at the caret on the meter scale in the viewfinder, and by the time I’ve done the calculation, and made the change, the birds have landed. It only takes a few seconds, but that’s enough to miss the shot.
I was able to get this shot, in literally the conditions I mentioned here, because I was in Manual mode, and my exposure was set for optimal exposure of the cranes. It did not matter how dark the background was, because I had my exposure set for the cranes, no matter where they were.
Note that this is not the exact order that I really shot these crane images in. Although I shot the first two at F5.6 for 1/640 of a second at ISO 100, the light had changed for the last shot, and I was now at 1/2000 of a second at F4.5. I’m just trying to make a point here. This is certainly a scenario we’re faced with all the time when shooting wildlife like this.
Syncronized Landing
Let’s talk a little about setting the exposure in the first place. Whether starting from scratch or with a hint from a priority mode, you will probably want to set your aperture initially, based on the artistic effect that you are looking for with the depth-of-field. For bird photography that’s usually close to wide open, though you might want to close the aperture down just a tad for larger birds, especially if they are not so far away, like Eric’s pelican. Note that Eric closed down to F5.6, and that’s probably about right, though Eric could also have gotten away with F4 at this range as well.
Once you have decided on your aperture, you can then adjust the shutter speed to something fast enough to avoid camera shake. Eric photographed the pelican at 1/1000 of a second, which will avoid camera shake, showing again that Eric is indeed a discerning photographer. If we think though that he needed to increase the exposure by around one and a third of a stop, he would have need to use a shutter speed of around 1/320 of a second with an aperture he was using, which was F5.6. For a sharp image of a bird in flight, 1/320th of a second might have been a little slow, although pelicans don’t flap their wings that fast, tending to soar more than flap.
Ideally you’re going to want at least 1/500 of a second for birds in flight, but really to a degree, the faster the better. If we want to show some movement in the wings, of course you can go much slower, as I’ve done myself many times, but that does reduce the success rate of your shots, and would require a bit more explanation to do the subject justice.
As you get close to what you think your exposure should be while looking at the caret on the exposure gauge in the viewfinder, you should also check your histogram. I find that with digital most of the time you will want to expose for the highlights, and that means that the right side of the histogram graph will be close to the right side of the histogram box, but not clipping. Clipping means that the histogram is touching the right shoulder of the histogram box. It’s OK to have a little if you know that it’s in a part of the image that you don’t care about, or for specular highlights, but if you severely overexpose any important areas, you may lose detail there, and there’s no way to get it back, even if you are shooting RAW. There are times when you will totally blow out a part of the scene, and there are times when you’ll expose for the shadows, if that is the most important thing to you at the time. I covered this in more detail in Episode 81 of this Podcast. As a general rule though, shoot for the highlights.
Opposite to our previous examples, and more in line with Eric’s questions about the relatively dark pelican, if you are shooting a dark bird against a bright background, you do need to be careful not to let the background become too bright. If you overexpose the background too much, the bright areas start to bleed into the bird or your main subject, making the edges soft and even reduce contrast in the subject itself. Ideally, you’ll want to make sure that the histogram is close to the right shoulder, but not touching it, and be able to see on the LCD that your main subject is well exposed. Unless the shadows contain detail that you really need to show, don’t worry about the left side of the histogram at all.
Whenever possible, I like to use the RGB histogram, as opposed to the standard black and white histogram. This is because you can actually blow out parts of one or two of the Red, Green or Blue channels, without this being indicated in the black and white histogram, as it only represents an average of all the light values.
If as you set your aperture, then your shutter speed you find that your shutter speed is too slow, the next thing to think about is raising that ISO. Eric shot at ISO 100, so to really remove the chance of blurring the bird after reducing the shutter speed to 1/320 of a second, if necessary, he could have used ISO 200 at F5.6 for a shutter speed of 1/640 of a second which may well have been much better to help avoid subject movement during the exposure. Remember that the longer the lens, the more you have to think about camera shake because longer focal lengths magnify the camera movement. The point here is that keeping ISO in mind as your third method to change exposure is very important and can be the difference between getting the shot, and not.
I should say that I don’t want people to think that Manual mode is plane sailing, especially on days with patchy cloud, when it can be difficult to keep up with the constantly changing light. I am forever checking my exposure. You will need to keep your eye on LCD and that histogram, and make sure that the subject is nicely exposed. If the light changes and you start to blow areas of the image out unintentionally, remember that most cameras have a flashing exposure warning, where the parts of the image that are overexposed flash. Exposure warning is often turned on by default, but if it isn’t, look for exposure warning in your camera’s manual, and turn it on.
As you shoot, you can often locate a reference object to check your exposure on while waiting for the action to start again. This might be a mid tone rock or a wall or something. My trick for doing this in snow is to point the camera down to totally fill the frame with the snow and adjusting the exposure so that I’m around one and one third of a stop above zero. Remember that even in Manual mode you still see the exposure indicators in the viewfinder, so you are not alone, and also remember that meters are better these days, so in general you can forget the old two full stops for snow advice if you use evaluative metering. It’s around 1 and 1/3 of a stop now. Just make sure that the caret is where you need it to be and then wait for the action to start again.
So, after all that, let’s quickly get back to the second part of Eric’s question. Yes, overcast days are nice for portraits, because the sky acts as a large soft box, but when your subject is flying and the light is coming from above the only way that will actually help is if there is something underneath the bird to bounce some light back up into the subject. A field of snow like what I had in my earlier example photos is great for this. It’s much easier to get a well exposed bird in flight if there is light being bounced back up at the bird. In general though, for a bird flying in the sky on an overcast day, without a reflective surface below it, if the contrast between the bird and the sky is simply too great, the only remaining option that I’m aware of, is to use something like a Better Beamer flash attachment for this, which would enable you to bounce some flash into the bottom of the bird from a distance. In Eric’s case though, I don’t think the contrast was that great, so although the grey sky was never going to be that exciting, it would not have blown out with one and a third stop of exposure compensation, or by using Manual mode and exposing for the bird.
Note that I haven’t gotten into using the spot meter on your camera today, because not all camera’s have spot metering, and to be honest, if you follow the steps I mentioned to set your exposure, you shouldn’t need spot metering.
Finally, I also suggest shooting in RAW, especially in conditions where exposure is challenging. Not only does RAW give you the ability to more easily change things like White Balance in post processing, it gives you a much wider dynamic range, allowing you to save more detail in the highlights areas that you might blow out, it also enables you to bring out more details from the shadow areas of your subject during post processing. JPEG will throw away much of this detail before it writes the image to your memory card.
Anyway, that was very long to answer fundamentally one question. Granted, I tagged on the Manual mode stuff myself, because it comes up so often. I hope that you have found this episode useful though. I can assure you though, most people that start out on my Workshops thinking that they don’t need Manual mode, usual become converts by the end of the first day’s shooting. In that kind of environment, this is far from photographic snobbery. It’s more like photographic survival, and taking control to get the shots that you might not be able to get otherwise. If are never in situations where you need Manual mode, then don’t worry about this. Beware though. I’ve heard lots of people say that they don’t need Manual mode, when the truth is that they just don’t understand why they need it.
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by Martin Bailey | May 12, 2009 | Gear, Podcast
Following on from Episode 201 of the Martin Bailey Photography Podcast, I thought I’d post the transcript for Episode 190, in which I gave you ten steps to great long exposure images. So here goes…
Long Exposures can push a photographer and our gear a little out of our comfort zone, but they can also be a lot of fun. In April 2009 I was reminded of this when I did some long exposure photography over at a small harbor town called Ooarai, roughly translated as the Big Wash, in the Ibaraki Prefecture. I’ve been doing a lot of travelogue type podcasts lately though, so today I thought I’d move away from that and do a 10 step guide, but of course, interweave some of my real world example shots to make the points easier to understand.
Firstly, let’s make a distinction between Long Exposure and slow shutter speeds. I personally don’t like to use the term slow shutter speed in this case, because it’s pretty subjective. If you are shooting a flying bird at 1/60th of a second, this would be considered a slow shutter speed, if you were trying to freeze the movement of the bird’s wings, because it will be too slow to do so. It may not though be slow enough if you want to pan with the bird and create that beautiful sine shape made by capturing the wing movement. 1/60th of a second will also not be slow enough to make a large body of water smooth over into a dreamy blur. Anyway, let’s start looking at my 10 steps.
Step #1: Find a subject that will be complemented by a long exposure
As we get into Step #1, let’s bring up image number 1802, which will be on your screen now if you are listening in iTunes or on your iPhone, or you can view on the Podcasts page at martinbaileyphotography.com. So, the first thing you need to do, is decide on a subject that will be improved or have something accentuated by capturing it with a long exposure. It could be shots of fireworks displays, lightning strikes and car light trails. I’ve done all these, and have some example images, but maintaining my main nature photography theme, I thought I’d look at this landscape shot from almost a year ago, in Nagano prefecture here in Japan. I talked about it back in episode 141 as well. There are a few points that we’ll make while looking at this image, but the first, as I say, is finding a subject that will work with a long exposure. Your entire shoot doesn’t necessarily have to revolve around the Long Exposure shot. This image was very much opportunistic. But when I turned the corner on my way to the hotel, I saw the scene, and knew instantly that this would make a nice long exposure image. There were both heavy, textured clouds in the sky and a thick cloud layer in the valley, both of which would blur nicely with a multi-second exposure. It was also getting dark, with literally just a few minutes of light left in the sky, so I had to move quickly. This image was shot at F11 with ISO 100 for 20 seconds. Not incredibly long yet, but it was long enough for the clouds to move towards me, making this wonderful radiating pattern in the sky. This is accentuated of course because I was using a wide angle lens and the clouds closer to me appear to move faster than those in the distance. The 20 second exposure was also long enough to make the clouds in the valley blur making them almost look like a lake down there, behind the silhouetted foreground trees.
Yachiho Evening Sky #1
Step #2: Include a static anchor object
I find that long exposure images work well when you have something that will remain stationary in the image. It doesn’t necessarily have to be in the foreground, but if you don’t have something in the shot that doesn’t move, then the whole thing becomes a blur, and although that can work, it’s not going to be as powerful as having a rock solid anchor for the eye. In the image we’re currently looking at, the line of trees is the anchor. It’s a sharp, solid line for us to come back to, to keep everything in perspective, with that big sky adding drama to the scene.
Step #3: Use a sturdy tripod and good ball-head
Of course, if you are going to be doing long exposures, to keep the anchor object sharp, you’re going to need to keep your camera very still during the exposure and this requires a good sturdy tripod. One of the biggest mistakes people make when getting involved in photography is underestimating the value of a good tripod. It’s understandable, because when you first start out, you have the expense of getting a new camera, a few lenses, a camera bag, and these days if you don’t already have one you’re going to need a reasonably powerful computer and then there’s all the software. It seems to be never ending. So the last thing you want to spend a lot of money on is a $500 or even a $1,000 tripod. The problem is, at about the time you figure out why you need a tripod, you probably also find out that the one you picked up for $30 is about as useful as a chocolate frying pan. Don’t get me wrong, I did this myself. I’m right in there with you.
The game is still changing though, believe me. I thought I was doing just the right thing buying a nice Manfrotto tripod for around $450, and I stuck an Acratech Ultimate Ball-head on there, both of which are excellent pieces of kit, but when I moved from 12 megapixels with the 5D to 21 megapixels in the 1Ds Mark II and now also with the 5D Mark II, I found that with my longer lenses, like the 300mm F2.8, even my $450 tripod wasn’t quite cutting it. It had seen some wear though, but it was perhaps a bit small, and not really rated for such heavy gear either. The only way I could get things locked down enough for good sharp results in such high resolution images, was to buy a $1,000 Gitzo Tripod. The Acratech Ultimate Ball-head is still used from time to time on my second Gitzo Tripod, and it is a great ball-head, but my main ball-head right now is the Really Right Stuff BH-55. This is simply a work of engineering art. It not only operates beautifully, and locks the camera in position, stopping it dead with no effort, but it also looks and feels great. We can get into that in more detail in another episode though. The point is, buy the best tripod and ball-head or tripod head that you can afford, especially if you are going to be doing long exposure photography. If your camera gets blown around in the wind during the exposure you’ll end up with soft images.
Step #4: Use ISO and Aperture to go long, but beware of Diffraction
You should also use your lowest standard ISO for long exposures. Even if you are shooting in very dark conditions, set your ISO to the lowest standard setting, because if you start to bump it up, you’ll not only get shorter exposures, you’ll also start to introduce noise, where you really don’t want. Now, by the lowest “standard” ISO setting, I mean the lowest ISO rating that your camera has without going into any kind of expanded ISO. If your camera has expanded ISO settings, it usually means the manufacturer wasn’t comfortable making those ISOs available by default for one reason or another, so if ISO 100 is the lowest your camera goes to without you making any custom settings, then use that.
On my camera I usually use ISO 100 most of the time, but pretty much always unless I’m using the Highlight Tone Priority setting, in which case ISO 200 becomes my lowest ISO. Let’s bring up image number 1668, to help make this point. In this image, I was using Highlight Tone Priority to preserve the highlights in the snow. I don’t use Highlight Tone Priority much now, but at the time, that’s what I was thinking when I shot this image.
Snow and Stream
The next thing you’re going to want to think about is using a smaller aperture. Note though, that if you stop your lens down too much, you’ll find that diffraction starts to degrade your image. When we force light through a very small aperture, we start to lose resolution. It varies, but most lenses start to suffer from around F16. I generally tend to use down to F11, and only go as low as F16 when I really need to. F22 is for emergencies only in my book, and I only go there when I can live with lack of sharpness in my resulting image. I shot the first three images that we’ll look at today at F11 by the way.
Step #5: Use a Neutral Density filter when there’s still too much light
So, even when we have selected the lowest available ISO, and the smallest aperture that we are prepared to use, we sometimes still have too much light in the scene for the length of exposure that we want, and that’s when a Neutral Density or ND filter comes in. I’ll get back to what I used in the last image shortly, but for now, let me explain what an ND filter is. They are basically grey filters that cut out light without affecting the color balance of the image. They are rated with conveniently confusing numbers. An ND2 for example cuts out 1 stop of light, an ND4 cuts out 2 stops of light, and an ND8 cuts out 3 stops of light. There are much darker filters such as the ND64 at 6 stops, and the ND10000 at 13 stops etc. You may actually remember two wonderful PDF files that our good friend Landon Michaelson put together that we released with Episode 111. (Long Exposure PDF and Dark Frame Subtraction PDF). Well, I’m mentioning this right now, because the first document contains information on the various density filters and how many stops of light they cut out, so go back and check that for more detail.
Another type of ND filter that I should probably touch on before we move on, is the Vari-ND from Singh-Ray. This filter turns, a little like a Circular Polarizer, although contrary to common believe, it doesn’t simply use two polarizing filters to work. As you turn the filter though, you get a totally variable neutral density between 2 and 8 stops of exposure. Going back to the image we brought up earlier, I used a Singh-Ray Vari-ND filter in this shot to increase my shutter speed to 8 seconds. The Vari-ND is a bit expensive for what it is, and it can create some weird, unwanted effects with wide angle lenses in certain types of light, so it is not a magic bullet. But I find it works well with longer lenses, like the 70-200mm that I used here. I can’t remember exactly but probably dialed in about 6 stops of darkness for an 8 second exposure, which gave me this nice silky feel to the water in the shot.
Step #6: Take the guess work out of exposure
If you are using very dense neutral density filters, and you are working at a time of day when you can’t afford to do a multi-minute exposures only to find that you got it wrong and then the light is gone, you need to do a test first. The best thing to do is to meter and find your required exposure, maybe even shoot a text image, without the ND filter attached. Then when you are happy with the exposure, attach the filter and recalculate your exposure with the filter on. This will save you time, especially if your camera is using dark frame subtraction to reduce noise, and you’ll possibly also save yourself from making a mistake that could cost you your shot. You might recall that I mentioned an iPhone application called NDCalc back in episode 177. If you find the mental arithmetic difficult, NDCalc is perfect for calculating the new exposure in seconds, just by inputting your shutter speed before adding the filter and the density of the filter that you’ll attach.
Step #7: Focusing on what you can’t really see!
Focusing can be tough when it gets very, very dark. If you are working in normal light of course, and the darkness is coming from a very dense ND filter, the best thing to do is to focus before you put the ND filter on. If the front element of your lens rotates when you focus though, mind that you are careful not to rotate it when you attach the filter or you’ll throw your focus off. Even pushing on the front of the lens or grabbing the lens barrel can throw of the focus, so care is needed, but this will help you to focus while you can still see.
If it is already pretty dark, as it was when I shot the next image, number 2256, the chances are you no longer need an ND. Here I had some very faint light reflecting from the sea, but this exposure took four minutes at F8, so you can probably imagine how faint the scene was. I did a couple of things here though to focus, that I wanted to pass on to you. Firstly, through the lens, because there was a little bit of contrast, I could just about see when the outline of the main subject, which is the gate here. While turning the focus ring while looking through the viewfinder, I could just about make out the silhouette of the gate getting smaller as got into sharp focus. Once you go past the point where the focus is sharpest, it starts to get bigger again, so you just backtrack to where it was smallest and you’re there. If you have LiveView when you can faintly see, the image on the LCD can be noisy, but give it a try as well. Zoomed in to 5 times magnification, I could also see the outline of the gate getting gradually bigger and smaller as I moved in and out of focus.
Ooarai Torii (Shinto Gate)
If there simply is not enough light to focus visually, either through the viewfinder or on Live-view, you can try taking a powerful torch or flashlight, and actually throwing some light on your subject while you focus. If the light is powerful enough, it may even give your camera enough to auto-focus, but at the least, this should be enough for you to manually focus accurately. Be sure to actually switch your lens into manual mode though, especially if you use the default settings which have auto-focusing linked to your shutter button. You don’t want to manually focus then have the camera start to search for focus again when you go to trip the shutter. Also, if you are shooting with other people, you might mess up their photographs by shining a flashlight into the scene, so be aware of that. You could of course if you are alone use that same flashlight to do some light painting during your long exposure, which is fun, but that’s really another topic.
Step #8: Minimize camera shake with a cable release and mirror lockup
In addition to a good sturdy tripod, use a cable release or remote timer switch to avoid causing vibration with your hands when you press the shutter button to start the exposure. If you are using 30 seconds or less shutter speeds, you can use your camera’s timer, which will allow you to start the exposure, and then take your finger away from the camera, and allow any vibration to die down before the exposure starts.
If your camera has Live-view, and you use it, then you don’t need to worry about mirror lockup, because the mirror will already be up out of the way when you trip the shutter. If you don’t have Live-view though, or if at some point in the future the way Live-view works is changed, and that’s very possible because it’s still a new technology, you may need to set your camera to Mirror Lockup mode. This is basically where the first press of the shutter button makes your camera’s mirror jump up out of the way, exposing the shutter in front of the film or sensor, and then when you press the shutter button again, the shutter is opened and exposure starts. This helps to reduce vibration, caused by the mirror jumping up if you do that at the same time as you start the exposure. If you have a two second timer, you can often use this in conjunction with mirror lockup. What will happen is, if you set the two second timer and mirror lockup together, when you release the shutter, the mirror will lockup, and the two second timer will start automatically, and when the two seconds is up, the shutter is opened and the actual exposure starts.
Step #9: Use Bulb Mode
Most cameras’ longest shutter speed is 30 seconds. If you are going to go past thirty seconds, you’ll have to use Bulb mode, which is usually the B on the mode dial. This is basically where your camera’s shutter will stay open for the whole time that you are holding the shutter button down. Here, when I say shutter button, we’re talking about the button on the cable release, because remember, you don’t want to be touching your camera directly to start the exposure. You can hold the button down for the entire exposure, but most cable releases have a little slider that can be slid up or down, over the button once pressed, to stop it from lifting up again, effectively holding the button down for you. If you are timing your exposure, make sure that you use a stop watch with a beep when it gets to the time, or some sort of timer that will let you know when the time is up. If you use something like NDCalc that I mentioned earlier for the iPhone, not only does it help with the calculation of long exposures, but once you have the long exposure time displayed, you can start the count-down with the touch of a button on the display. It then plays a sound when the time is up, so you can stop the exposure manually. Of course before too long the iPhone will talk directly to the camera and stop the exposure for you, but we aren’t quite there yet.
The alternative to manually timing the exposure is a Timer Remote Controller like Canon’s TC-80N3, which allows you to dial in how many minutes and seconds, and hours for that matter, that you want it to continue to keep the camera’s shutter open. This is great for use in Bulb mode. You set the time of your required exposure, press shutter release on the Remote Controller, which is basically just a fancy cable release, and when the time’s up, the shutter closes. One other word of advice that kind of goes without saying, but I’m going to say it anyway, is when using bulb or doing really long exposure work, make sure you have fully charged batteries in your camera. It wouldn’t be much fun to get half way through a long exposure and your batteries die on you.
Step #10: Noise Reduction
Most cameras these days will by default automatically process images made with long exposures to remove noise. I find that the built in noise reduction in the camera and in Lightroom is enough for shots like the ones we looked at today. For this last shot, even with a four minute exposure, there was no real noise in the image after my camera had done its thing and Lightroom had applied its default noise reduction. Having said this, if you are shooting in warm conditions you can get more noise, and with longer exposures you can end up with a bit of noise. When I do have noise in my images, my favourite noise reduction software now is Nik Software’s Define, that can be found in the Noise Reduction package and the other Nik Software Suites. I also find that Noise Ninja from PictureCode does a good job of reducing the noise, and it’s highly configurable. There’s also a product called NeatImage, which is equally as good I believe.
Podcast show-notes:
Noise Ninja from PictureCode can be found here: http://www.picturecode.com/
NeatImage can be found here: http://www.neatimage.com/
Really Right Stuff are here: http://reallyrightstuff.com/
The Acratech Ballheads can be seen here: http://acratech.net/
The music in this episode is from the PodShow Podsafe Music Network at http://music.podshow.com/
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by Martin Bailey | Apr 3, 2007 | Fundamentals, Musings, Podcast
Today I’m going to answer a question that I received by mail from Listener John Grant about what in a scene I choose to meter from for optimum exposure. John asks, “Would you discuss exposure and how to get the best possible, from what to look for in the scene and where to place the meter of your camera. For example do you choose the highlights to meter from or something else?” Thanks for the great question John. I’ll go on to explain about what I look for in a scene, the metering modes I use, and why, and we’ll also get pretty heavily into looking at some histograms. Much of what I say about histograms or at least the checking of them in the field will not be relevant to film users, but the histogram is a key part of my shooting these days, and I wouldn’t be able to talk about metering and the confirmation of results, without getting into some details. So if you are a film user, please bear with us on this, but if you are scanning your film and post processing in a tool like Lightroom or Photoshop, the histogram discussion will still be relevant. Anyway, let’s see if I can explain my methods in a way that will help John and all of you in some way.
Well, it turns out that John’s question is formatted in such a way that it really does help me to answer, because it’s very important to think about the scene you’re about to photograph before you consider what to meter on, and how to use that information. The first thing I do when getting ready to shoot a scene is look, and think about what is in the scene. Obviously, I’m doing this already from a compositional perspective, but I also start taking note of the light in the scene at the same time. If the scene is relatively evenly lit, without too many highlights, whites or other bright colours, or too many dark shadows or large black or dark coloured objects, then it’s all really quite easy. I can just throw my camera into Aperture Priority mode and leave the exposure compensation at zero, and start shooting. I will though still take a look at the histogram after the first shot or so and make sure that I am not over exposing anything. I find that with digital, unless the main subject I’m trying to depict is in deep shadow, I rarely worry too much about the shadows. There will be times when we will need to make sure there is some detail left in the shadows, but far more often, it will be the highlights we have to take care of.
I’ve said many times that I believe we should always try to get exposure as close as possible in the field, and I really don’t like the trend towards sloppy shooting and then fixing in post processing. Of course, everyone is entitled to their own way of shooting, but I personally want to give my images a chance to be as best as they can. If you shoot a great photo, then the first thing you have to do is push the RAW or JPEG file by two stops before you can even use the image, you’re not giving it much of a chance in life. Anyway, whether we’re talking highlights or shadows the one thing to always bear in mind is if depicting your subject in the way you’d like depends on having detail in either the highlights or the shadows you have to get the exposure right or close to it. Once you hit total black or pure white, there is no detail to draw out of that area of your shot, so no amount of post processing will bring it back, no matter what tools or techniques you use.
So let’s talk a little about the histogram, our main tool for checking to see if we’re on the right track. You may have heard that a histogram should be a nice hill or mountain shape, with a peak or a number of peaks around the middle and the slopes of the hill tapering off to the left and right sides. This is a good description of the histogram for an averagely lit, or I suppose I should say a properly exposed scene without too much dynamic range. That is without too much highlight or shadow. Not a perfect example, but let’s take a look at a shot from last Saturday, as it’s still fresh in my mind. I’m not going to go into details about the shot itself, but rather concentrating on the histogram. If you are going to view the image by punching the number into my Web site’s top page or podcast page, it is number 1366. Now, if you are listening to the Enhanced version of this Podcast in iTunes or on an iPod that supports Enhanced Podcasts, that have the M4A extension, you’ll be able to see the image right now and next we’ll look at the histogram. If you are following in another tool though, to continue, you’re going to have to go to the Podcasts forum at martinbaileyphotography.com and look at some images I’ll add as a companion post for this podcast. In fact, for the forum post, I’ll put an image of the whole of my Lightroom window, so you can see the image under discussion, and its histogram. I’ll also put a link to that in the show-notes to save searching around for it.
Cherry Blossom 2007 #9
Anyway, you’ll see in the first image some nice pretty pink cherry blossom. I’m going to get into how I shoot and some metering mode stuff soon too, but for now, just note that I was using my camera in Manual Mode, as opposed to Aperture Priority and the metering mode was Centre Weighted. You can see that there are lots of bright areas in the shot, and there is a darker background than the flowers. This is why I switched to manual mode. Next though, I’m going to display the histogram for this shot in the Enhanced Podcast. I’ll throw just the histogram file into the MP3 version as well, in case you are flicking through the images yourself in iTunes, but otherwise, please just go to the forum and view the histogram in the snapshot of Lightroom. You’ll be able to see that this first histogram is a pretty typical one. You’ll see that we have some nice rounded hills on the right hand side, which is going to be those nice pink flowers, and as we look across to just left-of-centre, we can see the multiple peaks which represent the slightly darker areas of the background. We can tell from this histogram that no areas are over or under exposed. We know this, because the histogram slopes off nicely at both the right and left sides, which means there’s no clipping. None of the data in this shot is exceeding the dynamic range of the camera image capturing ability.
So, before we go on and look at some other examples and their histograms, let’s talk about metering modes, how I metered this shot, and why. Most of the time you will probably be perfectly fine to use your camera’s Evaluative Metering mode. This is where the camera takes meter readings from the whole frame, and uses a multitude of algorithms to guess what you are after, and from what I hear, does a pretty good job of setting your exposure. I say from what I hear, because I’ve only heard that this metering mode is getting quite reliable these days. I personally got used to using Centre Weighted average metering some years ago, and never switched back. Note too that I’m using the Canon definition of Centre Weighted, which is where the camera metres the entire scene but gives priority to the values metered from the centre of the frame. Please don’t confuse this with Partial Metering, which is where the centre 8% of the scene is metered, or Spot metering, where just the centre 3.5% of the scene is metered. And if you’re a Nikon user, I believe Nikon uses the term Centre Weighted to refer to what Canon calls Partial Metering, so if I’m not covering your own camera’s terminology, please check your manual for information on the various metering modes available.
I find though that centre weighted just fits my shooting style. I probably use it for 98% of my shooting. It gives me a less computed, straight reading of the light in scene, so I know from experience when I’m going to need to use exposure compensation and when I’ll be OK. I may well be able to get away without using exposure compensation as much as I do if I was to give Evaluative Metering a try, but I just don’t seem to be able to kick the habit of using Centre Weighted. By all means though, if you are used to using and are happy with Evaluative Metering, continue to use it. I’m not suggesting you change your own shooting style.
The other metering mode I use is spot metering. Not all cameras have this, and before buying the Canon EOS 5D which does have it, I used the Partial Metering, which as I mentioned earlier meters the centre 8% of the frame, as opposed to the centre 3.5% for Spot Metering. Again, this can vary by camera, so please check your camera’s manual if you want accurate figures. Anyway, as I know that the pink blossom in the scene we have just looked at are quite light in colour, and likely to require around plus one stop of exposure compensation, I can just use spot metering, because the target is very small, and meter of one of the flowers. In this shot I chose to spot meter from the flower just left and slightly above centre, which is also the flower I focussed on. This is probably the first actual straight answer to part of John’s question. I meter from the highlight, and when appropriate, the same part of the scene that I am going to be focusing on; the main subject. I will then use that as a base for any exposure compensation that I know will be necessary. If you’d rather not use Manual Mode, what you can do is set your camera to say plus one stop of exposure compensation because we know the flower is quite a light colour, and then once you’ve spot metered from it, push your exposure lock button. This will hold that exposure for a number of seconds while you recompose the shot. This is of course not necessary if you’re metering from something in the centre of the frame, because you won’t be recomposing.
If your scene includes something large areas of something very bright or very dark, I would remain in centre weighted metering mode. I only use spot metering for getting a reading from a small object in the scene. Let’s take a look at another example, image number 1203, in which we can see a shot of a Red-Crowned Crane from my December 2006 trip to Hokkaido. Note how the bird and snow in the background take up most of the shot, yet it is not under exposed. When I’m shooting these white birds, or anything that I want to shoot that may move from a light background, as in the snow in this shot, to a dark background, such as the dark trees that form a back drop at this particular location, I usually switch to manual mode as I mentioned earlier, and take a reading from something that I know is the same colour as the subject, in preparation for something actually happening, like this bird coming close to me and doing a bit of preening. In the case of these cranes, they are the same colour and reflectance as the snow, so the first thing I do when I turn up to shoot these cranes is set my camera to Manual Mode, and point it down at the snow, filling the frame with it, and having set my aperture for the required depth-of-field, I adjust the shutter speed while looking through the finder, keeping my eye on the exposure indicator. That caret that moves up and down the scale that tell you how much higher or lower than zero your exposure is. Remember that the camera is trying to make everything 18% grey, and doesn’t know that I’m pointing my camera at a totally white scene, so I have to use my own calculator, that storage device between my ears to recall how much I have to exposure compensate for snow, and that is around 1 and 2/3s of a stop on a relatively bright day. So once the caret is pointing to one and two thirds above zero while pointing my camera at a totally white scene, I know I’m set to go. I will again shoot a few test shots and check the histogram before things start to heat up. Once you’re set up, no matter what colour the background is, I know I’m going to have perfectly exposed cranes and snow. If the light changes, I will of course have to change my exposure, so I tend to keep an eye out for light changes and repeat this exercise throughout the day, especially in the first and last few hours of the day when light changes pretty quickly. Note that if there was no snow, but I still wanted to avoid exposure mistakes, I’d probably switch to spot metering here again and just meter off of one of the birds, even if they were some distance away.
Preening
So let’s now take a look at the histogram for this shot as well. This time you’ll see a large spike over on the right side, but not touching the right shoulder. This represents all white in the shot. There are various shades of grey in the background made by the texture in the snow, which we can see by a very small band of information across the bottom centre of the histogram to the left, and then at the left, there’s a couple of small spikes again. These are of course the dark grey and blacks of the bird’s neck and tail feathers. You can see that I’m perhaps even touching the left side there, but there isn’t a spike, this means that some parts of this black are perhaps clipping, but I’m not going to worry about that, as I would much sooner see nice pure whites, than any more detail than this in the black tail feathers. Note too before we move on that the photo here is exactly as it was captured. This is the RAW file. The only thing that you’ll notice is that I have left the Lightroom default of adding +50 to the brightness. I’m not sure right now why that is the default, and I actually removed it for a while when I first started using Lightroom, but decided most shots looked fine with it, and left it that way. I do though reduce or remove this totally if this causes a shot to start clipping when I don’t want it too.
Let’s start to look at some examples though where I really would concentrate on the main subject, even at the expense of the dark areas, and sometimes even playing off of those dark areas for effect. In image 1360, shot last Friday morning, which for the sake of those catching up on the archives later was the 30th of March, 2007. Here you’ll see again, some cherry blossom flowers, this time though against a very dark background. I’m not going to go into much detail about the shot as I might well do a Podcast on these images in the near future, but what I need to say is that I was shooting these flowers shortly after it stopped raining for two reasons. One not relevant is because I wanted to capture the blossom with the droplets still on them. The second and more relevant reason is because when it rains, cherry blossom trees’ bark become very dark in colour, and this enables me to get the very effect I was aiming for, which we can see here. There is so much contrast between the bright blossom and the trunk that I have no way of capturing both with my camera’s sensors dynamic range. Now I know someone is already thinking of mailing about using HDR or High Dynamic Range technology to overcome this, but please don’t miss the point. I want these dark areas. This was what I visualized.
Cherry Blossom 2007 #3
Let’s take a look at the histogram for this image as well. We can see now that I have a small, pretty broad hump along the right side of the histogram, stopping just short of the right shoulder. This is of course the cherry blossom itself. Then there is almost no information for most of the left half of the histogram, until the last 10% or so, where we see a large spike, going right the way to the left side. So as we see in the shot, this is representing total black in some parts of the wet bark that contain absolutely no detail what so ever. I chose to go this way to not only allow me to capture the flower faithfully, but to also increase contrast between the main subject and the background.
Cherry Blossom 2007 #12
Here again, I’m metering for the highlights. So far that’s three out of three. Let’s look finally at an example of where I have metered for the darkest part of the shot, allowing other areas to be totally over exposed and blown out. In shot number 1369 we can see a cherry blossom tree shot from below with a wide angle lens. In fact, I’m not going to talk about this lens today, but it was shot with the new Canon EF 16-35mm F2.8L II USM lens. All I’ll say for now is that after shooting a few shots today, including the one we’re looking at right now, Canon have made a very good job of redesigning this lens. Anyway, in this shot we can see that I have exposed for the small batch of blossom near the bottom of the tree trunk, allowing the overcast sky visible through the canopy of the tree to be totally over exposed. Let’s again look at the histogram for this shot, and we’ll see that this time because the tree trunk was not wet, even with exposing for the flowers the tree trunk is not lost in the shadows. We can see this by looking at the small peaks to the left of the histogram. They are touching the left shoulder, but not spiking up it at all. There’s then a steady slope going from the left third, getting higher towards the right, which is all the pink blossom across the frame, then a nice big fat spike on the right shoulder. This is the overcast sky, totally blown out at the top of the shot. This was of course intentional. It was an overcast day, so the sky had nothing to add to the shot, so I used it’s brightness to add a beautiful surreal effect to the flowers in the canopy. I was again in Manual mode, but could have used any of the technique mentioned today to meter for this. I’m really just showing you this for an example of when I will not expose for the highlights. I must admit though, it is not that often that I do this. I used this image today, as I shot it only this morning, and it fit the bill. Also I didn’t want to go searching through my gallery for another example.
So, we’ll start to wind up a little here, but basically if you are not really sure what part of your shot you should meter from, but are not sure either that it’s going to be a straight forward “trust my camera’s meter” exposure, switching to spot meter mode or partial metering if you don’t have spot metering, and just take a reading from the various parts of the shot that you are concerned about. Although you can do in Aperture Priority or Shutter Priority by noting how the shutter speed or aperture settings change, it’s far easier to switch to Manual Mode and just watch that little caret move up and down the exposure indicator in the viewfinder. You might find that some areas of the shot are actually a little brighter or darker than others, and this will start to guide you in your decision as to what to meter for. If you don’t have much time to play around, or still don’t know what to meter from, try to find something mid-toned in your scene. If you are outside a good thing is grey rocks, or concrete pavement or sidewalk. And as long as you’re shooting digital and have a histogram to look at, you can always just take a test shot and check it and adjust your exposure accordingly.
Also, if you can select an RGB histogram in the custom settings of your camera, I suggest you use it. It will really help to spot if just one of the colours is blowing out, because this is not always noticeable in the standard brightness histogram. Red for example might be hitting the right shoulder in a photograph of a field of poppies in bright sunlight, but when viewing a normal averaged out light histogram, this will not always show up. If you use an RGB histogram, you’d be able to see Red clipping very easily, and reduce your exposure accordingly.
So, in summary, I basically expose for the highlights pretty much most of the time. This is because the highlights in a digital photo are the first place that I feel really stand out when exposure is a little off, far more than totally black shadows. This is not a hard rule though. As in the last example I looked at, you might want to let the highlights blow out sometimes as well. One thing to watch with blown out highlights that we shouldn’t finish without mentioning is that they bleed. If you have an area of overexposure the light tends to spill over into neighbouring pixels and you will lose detail in darker areas close by too. This may be the effect you’re after, but keep it in mind as it might not always work for you.
Also, I mentioned HDR or High Dynamic Range images earlier. This is something that I’ve not really gotten into very much, although I would like to. Basically you shoot multiple exposures of the same scene and then use Photoshop or another tool to blend the shots together and create a single image with a very wide dynamic range, much wider than any of the current cameras on the market can create. This is an option, and it might be for you, so worth bearing in mind. Also, I have mentioned in previous episodes about using gradual neutral density filters or blending multiple images in Photoshop to get around the dynamic range limitations of our cameras, but I’m not going to go over that again today.
Finally, you’ll have noticed that I called this episode “Metering for ‘Optimum’ Exposure” not correct exposure. In the past, I used the term correct exposure and was promptly taken to task on this, and rightly so. As the photographer, we decide how we want to portray the world captured in our images. We might decide to use high-key or low-key techniques, in which certain areas may be well over or under exposed, but if that is what we are aiming for as artists, then it becomes correct. By saying optimum though, I’m giving us the leeway to make the exposure exactly how we want it to be, not some predetermined ‘correct’ exposure, if there could even be such a thing.
So that’s it for today. Thanks very much to John Grant for the great question. I hope I’ve answered it sufficiently. If anything remains unclear, please do drop me a line and I’ll try to provide more information. Remember that if there’s anything that any of you have questions about, please do drop me a line or record an audio message using the MobaTalk applet on the top page at martinbaileyphotography.com. If it’s something that I already understand and have experience with, I should be able to get around to doing an episode on it at some point.
Anyway, with that I’d just like to say thanks for listening, and have a great week doing whatever you do. Bye-bye.
Show Notes
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by Martin Bailey | Nov 2, 2006 | Fundamentals, Musings, Podcast
This week I’m going to answer a number of questions from listeners, and we start a new service. Not only can you now leave recorded messages and greetings, that I will include in the show intro. Also, thanks to an idea by listener Mojo_Yugen who’s real name is Brian Schultze, I’m also now asking you to send me in a recording of any questions you might have. If I can answer based on my own experience, I’ll do so in a future episode, and of course, that will be followed by my playing the recording of question. To record you message or question, just go to martinbaileyphotography.com and look for the applet on the top page under the Record Audio Greeting section. If you click on the leave a message button you will go to a special Web site at MobaTalk, to record and leave your message. You can currently only record 2 minutes at a time, but if your question is longer, record it in multiple messages, adding something like part 1, part 2 to the title, and I’ll stitch them together for the Podcast. If you’d prefer, you could just record your question on your own machine, and send it to me in mp3 format by email at info@martinbaileyphotography.com. I am still open to questions by mail too if you don’t have a mic, and you can contact me on the same email address, or via the Contact Form at my Web site, or with the private mail function on the Forum at martinbaileyphotography.com. Anyway, thank for the idea Brian, and let’s get on with today’s main topic.
So, quite often I receive questions via email about topics that I’ve covered in the Podcasts, and sometimes just general questions. The answers to these questions are often quite valuable, although they are only shared with the one person that asked the question. If nothing else, I’m sure there are a few people out there that have thought the same things, and so hopefully these Q&A sessions will be of some use to most of you. So today, I’m going to talk about a number of things I’ve been asked recently, and then in future, maybe once a month or so, I’ll do follow up Podcasts to discuss topics either asked of my in email, or hopefully via audio recordings either mailed to me or recording on line with the new applet I’ve add to the top page.
So, the first question for today is from Robert in Germany. Robert had a question with regards to the photo of the waterfall with the rainbow, that I spoke about in Episode 11 called “Good Planning… Good Luck!” Robert asks “Why did you use a PL filter? As you explained in the Podcast you took the risk of eliminating the rainbow. Would not a gray filter also be possible to filter away some light?”
Let’s take a look at the image in question, number 731, as I explain my thought process here. Firstly, what Robert says is exactly correct. I did say in the Podcast that a PL filter can be used to pretty much eliminate a rainbow, and it can. Well, a few days ago when I replied to Robert by mail, I said that I had left my Neutral Density filter in the car, but as I don’t have the best memory in the world, I checked the notes for Episode 11 and found that I did have the ND filter with me, but attaching a Cokin filter holder and then fitting the ND filter takes a little bit of time, and the light was only going to be there for a moment or two, so I realized that I was not going to have time for that. But I did need a slow shutter speed to make the water look like it’s flowing, and I needed it quickly. First I lowered my ISO to 50, and the aperture to F22, and still I couldn’t get a shutter speed slow enough to make the water flow as much as I wanted, and we can see in the resulting photo. Without doing anything, I was faced with a shutter speed of 1/50th of a second, which would have introduced some motion blur, but I wanted a little more. Anyway, my only realistic option was the PL filter in my pocket, which I could attach much more quickly.
Kegonnotaki Rainbow
A PL filter cuts out around 2 stops of light so the shutter speed dropped from 1/50 of a second to 1/10, which was enough to give a flowing effect in the water without going over the top. There is risk as I mentioned, but if we remember the effect a PL filter has on a blue sky, you will recall that as we rotate the filter while looking through the finder, at some points the sky looks very pale, and other points it can become a very deep blue. The amount of effect the PL has depends very much on the conditions, but I’m sure you’ve all seen this effect to some extend. A PL works by cutting out the scattered light that bounces off shiny surfaces and water particles in the air. For this to work though we have to turn the front element of the filter until it aligns just right with the light coming straight at the camera, cutting out the scattered light. Of course, as a rainbow is basically just light reflecting off water there is the risk of erasing the rainbow pretty much completely. If we continue to turn the filter to the other extreme, checking as we turn it, you can see that it stops having any effect on the scene for a while, until we turn it past that point.
While shooting the rainbow and the falls, I could check the effect very easily. As I turned the filter, at some points the rainbow completely disappeared, but as I continued to rotate, it came back in full colour. I have to admit, I was a bit worried, but having checked the shots with and without the PL filter after getting home, the end results had no difference in colour what so ever, except the slower shutter speed has increased the flow of the water, as anticipated. All in all, it was a bit of a gamble, but in hind-sight, I don’t think this was a bad move. So if you find yourself in a pinch, either you don’t have a Neutral Density filter with you, or you just don’t have time to fit your filter kit to the lens, you can possibly make do with a PL, if you are careful to ensure it is not having the wrong effect. Also note too that I bought a circular ND8, which is a three stop neutral density filter after this, so now I have something that I can quickly drop on to the lens without having to play around with the Cokin system. I do still think the Cokin system is excellent, but only when I have the time, which is really still a very small amount of time, to use it. Anyway, I hope that makes that a little clearer Robert. Thanks for your very astute question.
The next question I had was from a listener who’s name I won’t mention as I wasn’t able to get permission to do so in time. This is another reason why a recorded message will be great! Anyway, the question was about the last episode, number 59, when I spoke about my early morning shoot at the Shibutouge mountain pass. The listener asked why I used negative exposure compensation for my shots when they didn’t seem to have a great deal of contrast. Well, this is another great question. The reason for the compensation in shots like number 1141, which I shot at minus 2/3rds of a stop, is really just because I didn’t want the camera to falsely brighten up the image. If I had simply trusted the camera’s meter, it would have tried to make the scene an 18% neutral grey style exposure, which in this case would have been too bright. The sun was still behind thick cloud on the horizon, and not really lighting the scene at all. With my eyes, I could not see anywhere near as much detail as the camera captured in this 1.3 second exposure. So I was really just making up for the cameras tendency to miscalculate the exposure for non-average scenes. This is very much the same with a very bright scene, such as a sunlit field of snow. The shot would be metered at anything up to 2 stops below what it should be, as the camera is trying to turn the snow into an 18% grey. Now, we all now that a field of snow in daylight is white, not grey, so we need to reduce the exposure by 2 stops to capture it correctly. So, it’s not always about contrast. In fact, I’d say it’s less often about contrast. For high contrast shots, I often switch to manual mode to ensure I get it right, but that’s another story that I also covered recently.
Autumn Too Short
Finally, I received another question last week from a listener called Kris Bjornstad from Scranton, PA (USA), with regards to a recent experience when shooting a sunset. At first, Kris was shooting pretty much as the camera dictated, but then decided to stop down the exposure manually. With this, Kris got some great shots of a deep red, fiery sunset. The thing is Kris wasn’t sure why the colours became so rich and saturated as he stopped down, or reduced the exposure. I explained in a mail that the less you expose, the more saturated, or richer, colours get, to a certain extent. Let’s think first of what happens if you over expose an image. The colours get less and less saturated until eventually everything turns white, right? On the other hand, as you lower the exposure, the image gets darker and darker, until everything goes black. But if you underexpose, or use just a little negative compensation the colours move toward black, but not too much, making them darker and hence richer.
One thing you can try to prove this is to open a well exposed image in Photoshop. Hopefully you can find one with lots of colour in it. Then open the brightness slider and slide it to the far right. You’ll see that the image gets very pale and washed out, with very weak colours. Move the slider to the far left though, and you’ll see that the colours get much darker and at least for a while, much richer, or more saturated. This is really what Kristian was doing by reducing the exposure of the sunset, making the scene much more saturated, which is exactly what you want in this situation. The other thing you could do if you want to play is to go to my web site at martinbaileyphotography.com, and select “Colour Wheel” from the Quick Links pull-down in the top menu. Place your mouse over the colour wheel somewhere in the middle between the dark centre and the white outside area. If you then move the mouse pointer from the centre to the outside the colour gets paler and paler until it turns white. This is very much what will happen to that colour as you increase the exposure. If you go the other way, the colour will get richer for a while, until it starts to get too dark to really be what we’d call a well saturated colour, and then it turns black. This would be the same as reducing the exposure, until totally underexposing the image. You can also click on the colour wheel at any point to record the colours in the list along the left side of the screen for easier comparison as you move your mouse around.
So, I hope that has been of some help. Remember that from now on I’ll be trying to answer any questions you might have, that you can mail me or contact me from my Web site about, and also, the things I’m really hoping for, is if some of you could record your questions using the new message recording tool on the top page of martinbaileyphotography.com. For now though, thanks very much for your questions guys. {NOTE: The recording tool mentioned here was discontinued some time ago.}
So once again, I’m very late getting this Podcast out. I’m sorry about that. I’m still very busy with other commitments, but also this week we’ve have more web site problems that have eaten into my preparation time. I’ve also gone and caught a pretty nasty cold too, as you may be able to tell from my voice. I guess I’ve been burning the candle at both ends a little too much. Something else that I’ve found this week is that the Japanese text from both the forum and the titles and comments I add to the photos I upload in my gallery has all become corrupted in the server move in September. It mostly looks fine in the gallery, apart from a few tell tale signs, but when I looked into this, it seems that the jump from an older version of the database to the current version has broken all of the Japanese characters. I’ve figured out how to setup the database to behave correctly, and I have also figured out how to restore the old information, but it is going to require taking the gallery and then the forum down for 15 to 30 minutes or so each while I make the changes. I’m thinking to do this over this coming weekend, so if you come to the site and find either the gallery or forum down, please try again 30 minutes or so later, and everything should be up and running again. I am really sorry for all the continued trouble, and I’m still hoping that it will all be over soon.
Finally, if you haven’t voted for your favourite entry in the Reflections Assignment, please go to mbpgalleries.com and check out the Assignment Album, and make your vote. You have until the end of this coming Sunday, which is November the 5th. Once again, it’s tough, because the level of entries is so high, but it would be great if you could take the time to choose your favourite if you haven’t already. I’ll announce the winner and two runners up next week, and we’ll kick off the next assignment too, so stay tuned for that. And for now, have a great week, what’s left of it, whether you’re out shooting, or whatever you do. Bye bye.
Show Notes
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by Martin Bailey | Nov 5, 2005 | Art Talk, Musings, Podcast
Hello and welcome to episode ten. First, I want to announce the winner of October’s prize for members active in the forum. Congratulations to Marisa Firpi. An original print of the photograph you chose, which was “Distant Tokachi Mountain”, is in the post on its way to you. This is photo number 663 if anyone would like to take a look. The print was creating with an Epson PM-4000PX printer, which I believe is the Stylus Photo 2200 in the US. This printer uses pigment or archival ink, and I am using compatible paper, so you can expect your print to last longer than a standard photograph under the same conditions.
So, on to this week’s main topic… Today I’m going to talk about Exposure, Exposure Compensation and the times that I switch to Manual mode when shooting. There’s a lot to take in, so you might need to concentrate a little if you are not entirely confident in these areas.
Typically I use Aperture priority mode, but under certain condition I switch to manual mode and set the aperture and priority myself. I’ll explain more about that in a moment, but first, let me explain briefly about the relationship between the aperture size, the shutter speed and the ISO settings. For some of you this will just be a recap, but I’m sure some listeners will benefit from a brief recap.
When we talk about the aperture size, we often use the term f-stop. The f here stands for factorable. Basically, your camera will have a series of aperture values which you can set. The smallest number such as F1.4, F2.8 or F4 etc represents the largest aperture size, and the largest numbers, such as F22 or F32 represent the smallest aperture size. I know it’s weird to have the smallest number equaling the largest aperture and visa versa, but it would make this Podcast too long to go into the reasons why. Let’s just remember it this way.
The key aperture settings are F1, F1.4, F2, F2.8, F4, F5.6, F8, F11, F16, F22 and F32. Some lenses will go smaller than F32 to F45 or even F64, but they are not so common. With each stop, counting down from the smallest number, or largest aperture, we are effectively halving the size of the hole that lets light into your camera. Depending on your camera, you may also have half or third stops, but the numbers I just gave are the primary stop values, so let’s concentrate on them, and if you can, it will help you greatly when shooting in manual mode to memorize them.
Now, to help us to change these settings while shooting with some simple mental arithmetic, we should remember that there is a direct relationship between the Aperture values and the shutter speed and the ISO. To illustrate this, if you have your camera available you could try it right now, if not, just keep on listening. This will work on a digital camera or a film camera that allows manual setting of the ISO and see the aperture and shutter speed settings. First set your camera to aperture mode. Next set your ISO to 100 and aim your camera at a scene that you know will have constant light for a while, then half press the shutter button to have the camera meter the scene and show you the aperture and shutter speeds. Make a note of the aperture and shutter speeds. For the sake of this example, let’s say that you have set your aperture to F8, and the camera is giving you a shutter speed of one 250th of a second. If you then change the ISO to 200, you will now see that the shutter speed changes to a 500th of a second. Change the ISO again 400 and you’ll see that the shutter speed changes to one 1000th of a second. So we see that changing the ISO is doubling the sensitivity and therefore halving the time needed to make the same image exposure.
Now, let’s return the camera’s ISO settings to ISO 100, and you’ll be back to F8 at 250th of a second. This time, let’s change the camera’s aperture setting. Remember that F5.6 is one f-stop larger than F8, so obviously, when we change the aperture from F8 to F5.6, we’ll be letting in twice as much light. So what’s going to happen to the shutter speed? That’s right! It will be halved to one 500th of a second. This is the same as changing the ISO from 100 to 200, and doubling the sensitivity of the film or sensor. To make the point, let’s make the aperture smaller by stopping down to F11. Now you’ll see that the shutter speed changes from one 500th of a second at F5.6 through the original 250th of a second at F8 to 125th of a second at F11. If you stop down further to F16 you’ll again halve 125th of a second to on 60th. I know that half of 125 is actually 62.5, but your camera will display one 60th. Again, let’s just remember this as it is.
Of course, if you were to set your camera to shutter priority, you could do a similar thing by setting the shutter speed to 1/250th of a second, and the camera would select F8 for you. If you change the shutter speed to 1/60th of a second it would change the aperture to F11 for you. It’s all relational.
If by the way you are getting inconsistent reading while trying this, maybe you could try this at night under artificial lighting, such as the light bulb in your living room. You might also want to put your camera on the table or even on a tripod to keep it steady during the operation, so that the readings will be constant.
If you own a hand-held light meter, you can also play around with that in a similar way to get an idea of the relationship between these three settings.
Anyway, I think you get the picture. By changing any combination of the aperture, shutter speed or ISO we can change the amount of light that hits the film or digital sensor and change the exposure. Now that we know that a properly exposed image can be obtained by any combination, let’s talk briefly about EV or Exposure Value. Exposure Value is a unit used to describe the amount of light for any given exposure. For example, the starting point for the example given earlier, which is F8 for 1/250 of a second at ISO 100, has an Exposure Value, or EV of 14. And so do F16 at 1/60 of a second and F5.6 at 1/500 of a second and F2.8 for 1/2000 of a second. All of these settings will give us the same exposure as the same amount of light will hit the film or sensor. It may be easier to understand the relationship between the EV values and the shutter speed and aperture settings by look at a table I posted in my forum some time ago. I’ll include a link to this post in this episode’s notes.
Obviously being able to obtain the same exposure using different combinations of aperture and shutter speed, gives us the ability to make artistic decisions about the resulting image. That is because the size of the aperture will affect the depth of field. If we want the whole scene in focus, what we call pan-focus, we must select a small aperture such as F16 or F22 or smaller, though this also depends on the focal length of the lens and the distance from your camera to the subject on which you focus. Talking about this today though would make this Podcast a little too long, so we’ll leave that for another day. Anyway, pan-focus is often something that we want to achieve in Landscape photography to ensure that the whole scene is sharp for our eyes to explore.
If however, we want a very shallow depth of field, say for a portrait or wildlife shot in which a sharp background would detract from the main subject, we would need to select a wider aperture. So we may decide to go for an F2.8, F4 or even F5.6 aperture with longer focal length lenses.
Now, before we move on to some real-world examples, let’s talk briefly about exposure compensation. As I mentioned in last week’s Podcast, your camera will almost always try to render your scene in neutral brightness, similar to that of an 18% gray card. Now if the scene is actually very dark, say it contains a lot of black objects, or such as some of the images attached to last week’s episode, the camera will try to brighten them up and over-expose your image, so you have to under-expose to ensure that the scene is recorded accurately. Likewise, in daylight, if the scene is very bright, the camera will try to make it a neutral brightness, and therefore will under-expose the shot. So you have to over expose it to make it accurate. This practice is called Exposure-Compensation and most cameras except for the basic, fully automatic models will have the ability to compensate exposure quite easily. It’s usually as simple as turning a dial. You also need to know by how much to turn the dial of course, which I have some practical advice on.
So let’s talk about a practical application, now that we can do these exposure calculations easily in our heads. This will also illustrate the reasons why we might want to go to manual mode on occasion.
In February 2004 I went to Hokkaido, the northern-most island of Japan, to shoot wildlife. Hokkaido in February means snow, and lots of it. Snow will generally fool your camera’s meter into under exposing by around 1 to 1 and 1/3 of a stop in overcast conditions, or up to two stops in bright conditions. If you were to rely on your camera’s meter you would end up with gray snow, which I’m sure you’ll agree would not look very nice.
To make snow look white, you can compensate by moving your exposure compensation dial to plus one and 1/3, one and a half or more in brighter conditions. If the entire scene is going to be snow with no darker patches you need not worry about switching to manual mode, as the metering will be constant, so the amount of exposure compensation needed will also be constant. However, if the scene will be made up of very light patches, such as snow or light coloured sand, and dark patches, such as wet rocks or trees, depending of the metering mode you are using and where your main subject is in the frame, you camera can make all sorts of mistakes. It is under this kind of conditions that I would switch to manual mode and set both the aperture and shutter speeds myself.
Wassup!! – Japanese Crane
Let’s take a look at the first photo on today’s Podcast. This is number 287, which was shot at F5.6 at 1/800 of a second. You can view the photos in iTunes or on my Podcast page which is linked to the top page of martinbaileyphotography.com. You’ll see a number of Japanese Red-Crowned Cranes on a field of snow and a dark forest in the background. I had l metered from the snow which although I don’t recall exactly, was probably giving me a reading of around 1/2500 of a second at F5.6. The camera was remember trying to give me a nice medium gray coloured snow, so this was far too fast a shutter speed. It was a hazy sunshine on that day, not full sunlight, so I didn’t need to compensate by a two full stops. To find the correct exposure, I first took a shot of the snow, with nothing else in the frame, then compensated by adding around 1 and 2/3 of a stop.
To calculate this, you can either count up two thirds from plus one stop, or down from plus two stops. To count up from one stop, start with 1/2500 and then double the shutter speed to 1/1250 of a second. Then click twice more on your shutter adjustment to go past 1/1000 of a second to 1/800. To drop back by a third from two full stops, double the speed first to 1/1250 as before, then double it again, which will give you 1/640 of a second, which is two stops. Then click back one to 1/800. You don’t have to do the mental arithmetic to find out exactly what a third is, as you know that there are three clicks per stop. Your camera will help with the finer adjustments. In actual fact, if you don’t want to remember all this about doubling the times you can just think that 1 and 2/3 is actually 5/3, so you can just click five times after what the camera is initially telling you.
If you have your camera set to use half stops and not thirds you will have just one click between stops. You will probably also have different numbers to play with to start from. This makes the example a little confusing, but I can’t go back to February 2004 and take my shots again, so I’ll just quickly mention that when I set my Canon EOS 5D to use 1/5 stops, in manual mode I have the options of 1/750, 1/1000, 1/1500, 1/2000 and 1/3000 etc. If you are using a similar scale you need to set the shutter speed to 1/750, which would be one and a half stops more than what your meter reading gave you, which would probably have been around 1/2000 of a second.
One important additional piece of advice here is that if you are using a digital SLR, it is very important to check that you are not blowing out your whites. Take another practice shot and check the histogram. If you have a spike on the far right hand side it means there are areas of your shot that are too bright. With a very white scene you should see the peak of the histogram weighted to the right side, but not right up against it. Some digital SLRs also have a flashing warning when the white is close to or actually blown out. If you see either of these warning signs, drop down by a 1/3 or 1/2 a stop and take another practice shot. Repeat this until the histogram looks good or there are no or very little areas of the image flashing the over-exposure warning. This way you should be able to ensure that your whites are white, but not blown out.
Japanese Crane
Let’s also take a look at the second shot attached to this episode, which is number 297. This time the white cranes, which are obviously the same colour and luminosity and when they are standing on the snow, are now flying against a totally dark background. I shot them in manual mode at exactly the same settings, F5.6 at 1/800 of a second. Had I left this to my camera’s meter, it would have over-exposed to brighten the dark background, and the birds would have been so blown out that there would have been absolutely no detail in the white what so ever. The shot would have been useless. Instead, you can make out detail of the feathers and the background is dark as it actually was. Another interesting thing is that even when the birds were shot flying overhead at the same F5.6 at 1/800 of a second, as in shot 280, they were still perfectly exposed. This is another scene that would have fooled the camera’s meter and again ruined the shot.
Japanese Crane
Of course there are numerous ways to ensure good exposure in high contrast scenes, such as using spot metering on your camera and using hand-held light meters etc. but getting into this right now would make this Podcast way too long, and I still have some weekend left to enjoy, so let’s leave it there for now.
For some examples of when you might want to do some negative exposure compensation to ensure a dark scene stays dark, take a listen to episode nine and look at the examples. I introduced a number of dark shots from a trip to India.
This Podcast was a little heavy going, but if you are not familiar with Exposure Values, F-stops and exposure compensation, you might want to listen to it a few times until you come to grips with this theory and the practical applications. If you have any questions, I’ll try to answer them in the forum at martinbaileyphotography.com and if I can’t, I’m sure someone will be able to.
Show Notes
The Music in the first 28 Podcasts is copyright of William Cushman © 2005, used with kind permission.
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