26 Jun 2006 Macro Photography Part II – Larger than Life (Podcast 43)
As I said in last weeks episode, Macro Photography could never be covered totally in just one or two Podcast episodes. I actually thought at that time I would release two episodes for now and follow up with more later as I gain experience in macro photography and more tips for you. As when I was preparing for last week though, I’ve found that there is just so much that I want to say on this subject I’m going to keep going for a another episode making this initially a three part series. Again though, I’m really just scratching the surface. Macro-photography is such a complex subject that I’m really probably just scratching the surface of it myself in many respects. This can really be said about many of my Podcasts, but as I gain experience and learn more myself I will be following in future episodes. Today though, let’s touch on going larger than life-size, that is, magnification of more than 1:1. If you aren’t familiar with life-size shooting or what life-size or 1:1 means, or other terms like minimum focusing distance and working distance, I suggest to step back to episode 42 and brush up on some of these terms and some other basic macro techniques.
OK, so I was wondering in what order to attack the remaining subjects that I want to touch on, which are going larger than life size with the MP-E 65mm macro lens from Canon, and the focusing problems this causes. Also I want to talk about paralleling your composition when you have multiple subjects that you want in focus, and also using dedicated macro flash, and using a second flash to illuminate the background. I was going to leave talking about 65mm to the end, as it’s probably the most specialized of these topics, but thinking about it, once you start using a lens that allows you to get this close, all the other stuff I want to talk about becomes even more important, so although all of these things are still very relevant at 1:1 or life-size macro photography, I’m going to discuss going larger than life first today.
First to give you an idea of what I’m currently achieving with the MP-E 65mm lens, let’s take a look at image number 1023. Remember that I am now producing Enhanced Podcasts, so if you are listening on an iPod or iTunes, the image will have already changed automatically. If you aren’t listening to the Enhanced version you will need to go to my Web site at martinbaileyphotography.com and click on the Podcasts link to go to the Podcasts page. There are various ways to listen and view the images, but it’s all there on the Podcast page, so please take a look. Even if you are listening with iTunes, if you are at a computer, take a look at the Podcasts page anyway.
Getting back to image number 1023, you will see the stamen of a Chameleon Plant, shot at 3X life size. That means that the little yellow anther, the tips of the stamen, that have been recorded at about 1.8mm wide on my 36mm wide sensor, are actually 3 times larger at 1.8mm than their actual size in the real world. In this image they look like little peaces of yellow candy, but in actuality, these are only each around half a millimeter wide.
There are a number ways to shoot at larger than life-size. Last week I touched on using an extension tube, but you can also use extension tubes with teleconverters or Extenders as Canon calls it, and also other methods include using bellows between the camera and the lens to move the lens away from the camera but stop any light from entering the gap and you can also stack lenses or reverse the lens. A couple of books that I’ve read that explain these techniques are John Shaw’s “Closeups in Nature” and Tim Fitzharris’ Revised Edition of “Close-Up Photography in Nature”. Both give some excellent advice on all aspects of Macro photography both smaller than and larger than life size. There’s a link to these books on my Recommended Reading page if you are interested. Click “Recommended Reading” in the “Quick Links” section on the top page of my site to take a look.
I’ve read these books like a child with eyes wide open unwrapping presents on Christmas morning, but I didn’t follow any of the lens stacking or reversing advice myself. The problem with stacking is that you have to tape lenses together and to a certain extent butcher them, and I don’t have any lenses that I really want to do that with. There are adapters available that allow you to join lenses by the filter screw threads though. When reversing lenses, you loose auto-focus and often, again without butchering your lens to a certain degree, you have only wide open aperture which isn’t that much use at these magnifications because of the incredibly shallow depth-of-field. There are again adapters that allow you to reverse lenses relatively easily, but as I looked into this more, I found some devices to actually help you to reverse a lens and retain all of it’s functionality by linking it back up to the camera. The problem was this costs almost $1,000, which was only around $100 less than I paid for my final choice, which was a brand new MP-E 65mm F2.8 1-5x lens from Canon. This is fully supported for use with the Canon EOS camera range, and has a connector for the macro twin-lite that I’ll talk about next week, and I don’t have to butcher any of my existing lenses either.
So, as the name implies, the MP-E 65mm F2.8 1-5x lens allows us to shoot at up to 5 times life-size magnification. The shot we are currently looking at, as I said, was shot at 3x. The shutter speed was 1/200th of a second at F8, with ISO 200. I was using the Canon Macro Twin-Lite MT-24EX flash unit. As I say I’ll go into this in more detail next week, but in the simplest use you really just need to switch the camera to manual mode so that I could just select the shutter speed and aperture I wanted and let the flash do the rest. I often find that I reduce the flash exposure compensation by around two thirds of a stop, but apart from the, the camera really does do the rest.
From an artistic perspective, I’d chosen to shoot this subject almost from above, so as to maximize the drop off in depth-of-field as we look down the shaft of the flowers stamen with two of the four white petals filling most of the background. I’ve frame this shot to crop the petals slightly, but you can see that the petals end from the darker corners, allowing you to fill out the rest of the shot, orienting your mental image. The patch of green at the top was within the range of the twin-lite, so it has founds it’s way into the shot, which I don’t mind at all as it’s totally out of focus, but then the background falls into total darkness in the top left as it receives no light from the flash.
Natural light at these settings was not going to illuminate the background in any way. There are two reasons for this, the first is that I was working in a park like a small wood, with a dense canopy of leaves above and all around, and the sun was already quite low in the sky. The other reason in how this lenses aperture works. The smallest aperture of this lens is F16, which might not seem that small for a lens with an inherently small depth-of-field due to the very close working distance, however, the effective f-number is smaller than that displayed by the camera. This is due to the design of the lens and the fact that the f-numbers displayed are those for when the lens is focused on infinity, despite this lens not being able to focus on infinity.
The formula to calculate the actual aperture is f-number x (magnification + 1), with the magnification + 1 part in parentheses. So when you are shooting at F2.8 at 1 times magnification, or life-size, magnification of 1 + 1 equals 2. Multiplying the F2.8 of the aperture by two gives us 5.6, so the effective aperture at F2.8 is F5.6. If we go to a magnification of two, we have to multiply 2.8 by 3, to get get F8.4. In the same way, F2.8 at 3 times magnification becomes F11.2, at 4 times it becomes F14 and at 5 times it becomes 16.8. So even if I am shooting with the lens wide open at F2.8, if I shoot at 5 times I’m already effectively at quite a small aperture.
As we start to stop down the lenses aperture the same formula gives us F16 effective for F8 at life-size, then F24 for two times, F32 for three times, F40 for 4 times and F48 for 5 times magnification. If you recall, I was shooting image 1023 of the Chameleon Plant at F8 at 3 times magnification, so I had an effective aperture of F32, which doesn’t seem quite as wide any more.
The far end of the scale, F16 actually gives us an effective aperture of F32, 48, 64, 80 and 96 as we move through life size to five times magnification. As I’m using a camera with TTL or through the lens metering, apart from the fact that at high magnifications the viewfinder does become quite dark, I don’t have to worry about the small apertures too much as the camera does the calculations for me. The formula for setting the exposure manually though are +2 stops for life-size, +3 for two times, +4 for three times, plus 4 1/2 for four times and plus 5 stops for five times magnification.
OK, now I know this will start to give you a number overload, but before we move away from numbers, finally I want to let you know just how shallow the depth-of-field is at these apertures. Firstly, an interesting fact to note is that this lens only has a depth-of-field of more than 1mm when used at life size and stopped down to an F8 or smaller aperture. Any other magnification cannot give you a depth-of-field of more than 1mm. F2.8 at life size has a depth-of-field of 0.396mm. F4 give you slightly over half a millimeter. F5.6 gives you 0.792mm and from F8 you finally have 1.12mm, F11 give you almost 1.6mm and F16 gives you a massive 2.24mm.
Once you start shooting at two times or more all apertures give a depth-of-field of less than one millimeter. To just give you the extremes at largest and smallest apertures for each magnification, two times gives you 0.148mm at F2.8 to 0.84mm at F16. Three times gives you 0.088mm at F2.8 to 0.498 at F16. Four times gives you 0.062mm at F2.8 to 0.35 at F16. Finally, at five times you get a depth-of-field of 0.048mm at F2.8 and 0.269mm at F16. And that’s it for number for now.
By now you are probably wondering how you switch between the various magnifications and how you focus this lens. Let’s take a look at a photo of the gear I used for this last shot to make it easier to explain. In image number 1022 you can see my Canon EOS 5D camera with the MP-E 65mm macro lens, the Canon Macro Twin-Lite MT-24EX flash unit and the Canon Angle Finder C. All of this is sitting on a Really Right Stuff focusing rail, which I’ll explain in detail next week, but is basically used for fine focusing by moving the camera back and forth. In this shot the lens is fully extended to 5 times. The 65mm lens is actually only 10cm or 4 inches in length, which is a little longer than the focusing ring on the barrel that we can see in the middle of the lens here. This length is when the lens is set for 1:1 or life-size photography though. As you turn the focusing ring, the lens extends from the front and back as it zooms through the magnifications from life-size up to 5 times magnification, which is what we see here with the lens fully extended.
Now if you notice, I’ve just said we turn the focusing ring to zoom through the magnifications. So how do we focus? In practice, you can turn the focusing ring to make focus adjustments, but as this is changing the magnification, if you want to retain the magnification, you must move the camera back and forth, and even then, the amount of focusing possible by turning the focusing ring is minimal, because as you turn it more, the magnification changes so much that you have to recompose the shot. In my last shot, where I wanted to just partially crop the flower petals, had I used the focusing ring to set the focus, the whole composition would have gone out the window.
By the way, as I mentioned earlier, this lens cannot focus to infinity. Unlike the 100mm macro or other macro lenses that can focus to infinity and therefore double as portrait lenses etc. the MP-E 65mm cannot. The minimum focusing distance, measured from the film plane or sensor is 24cm at 5x to 31cm at life-size. The working distance, that is, the distance from the front of the lens is fractionally over 10cm for life-size, and just over 4cm for 5 times photography. The focus for any given magnification is a constant. It cannot be changed. The only thing you can do is change the magnification, allowing you to effectively focus anywhere between 24 and 31 centimeters, or move the camera back and forth so that the subject falls at the right spot for any given magnification.
So now I’m sure you will be able to appreciate that with depth-of-field this shallow, no practical way of focusing the lens well without moving the camera back and forth, and effective apertures as small as F96, this is not the lens for the faint-hearted. With the slightest breeze causing subject movement blurring your shots to boot, if you want to go larger than life-size, you’re going to have to take some extra precautions that you don’t need to consider right now. Last week I mentioned that it took me around 9 months after I brought my 100mm macro lens to really start getting shots that I was pleased with, and that was at a maximum magnification of 1:1. Sure I was not spending a whole lot of time trying to overcome the difficulties, and now that you have learned by all my mistakes it should definitely not take as long, but I am really just pushing the point that macro photography takes a lot more patience than most other types of 35mm photography. Once you go larger than life-size though, we have a whole new bunch of difficulties and limitations thrust upon us. If I haven’t bored you silly already, and you are still interested, tune in again next week. I’ll finally get around to explaining some ways to make life a little easier.
So that’s about it for today. Some of you will have found this heavy going and there is now going to be one more part to this series, for now anyway.
One piece of housekeeping before we close is that I will have locked the Rainy Days assignment album by the time most of you listen to this episode and voting will have been turned on. There’ll be a small black “Vote” button above the photo when viewed full size, and you will be able to change your vote after you’ve voted until voting end. I originally announced that voting would be possible until the end of Sunday the 9th of July, but I might need to bring this in by a few days for personal reasons. I’ll then announce the winner and enable comments and rating in the Assignment forum after that.
So that’s it for this week. Have a great week what ever you’re doing. Bye bye.
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