24 : "Let's Get Small"
This week I hand the soapbox over to photographer and writer James Harbeck. Through his blog Sesquiotica, James appreciates and dissects the fine details of words; here he explores our visual world at an equally fine level of detail. Not just a visual connoisseur, James also shares technical details about how to make the minuscule come into focus without the need of expensive equipment.
I love taking pictures of small things.
I love it because it gives me a new way of seeing. I get to see details and perspectives that I am not normally privy to.
I love it because it is dreamy.
It is dreamy because of the shallow depth of field. Even if you stop down your lens, the background slides out of focus quickly. When you shoot very close and wide open, the depth of field is not paper-thin. It is thinner than paper.
And it can be very easy to achieve. Very easy and not very expensive.
Obviously, there are macro lenses you can buy. And pocket cameras often shoot very close just because their actual focal lengths are so small (due to their small sensors), so the focal distance can be smaller while maintaining the same ratio of focal distance to the focal length. Check out how close you can focus your smartphone!
But you don’t need to buy an expensive lens or pocket camera, or to put up with the reduced resolution and colour depth and the increased depth of field from a smartphone or pocket camera. I do most of my macro photography with old non-macro manual-focus lenses attached to an interchangeable-lens camera.
There are two main ways to make a non-macro lens a macro lens. They relate to the optics of lenses.
The first way is to use a macro lens attachment on the front of the lens. You can get some that screw into a filter ring. But I really like this Raynox macro lens, which has a spring-loaded attachment that lets it clip into most lenses.
It works quite simply, pretty much like a magnifying glass. The focal distance is reduced, and the depth of field reduces with it proportionately. It has no effect on the exposure or relative f-stop because the lens is the same focal length and the same distance from the sensor. How good an image it gives will depend on how well it’s made. The Raynox is pretty good.
Let’s see the effect it has on three Canon FD lenses: a 135mm f/2.5, a 50mm f/1.4, and a 28mm f/2.8. I’ll use this stuffed cat to demonstrate.
I’m shooting in low domestic light because I can’t be bothered to move more light sources to my table when I’m going to have to use a tripod anyway. (I can shoot in daylight without a tripod – see the grasshopper above – but in low light the exposure is just too slow; a slight tremor of your hand becomes an earthquake at this magnification.)
Here is how close my 135mm gets.
And here is what it sees.
Use the 50mm and it shoots from this close.
And sees this.
The 28mm gets a little closer because wider lenses can generally get closer, but the angle of view is such that it doesn’t get as close in with the macro lens.
If the lesson of that seems to be that you should use longer lenses for macro, well, that only works when you’re using a macro lens on the front. Extension tubes and bellows, which are the other way to make a lens macro, are a whole other thing.
There are two important things that photographers should know about focal length, focus, and depth of field. You probably know the first, which is that depth of field is a function of four things:
1. How close you’re looking at the image. Technically, only the exact plane of focus is in perfect focus, and for everything else points become circles, causing blur. But the limits of the resolving powers of your lens, your sensor, and your eyes when looking at the final image mean that circles below a certain size are small enough to look like points to you.
2. Your relative aperture, i.e., your f/stop. The lower the number, the wider the aperture, which means the circle is bigger for any out-of-focus point, which means that more points look out of focus, and out-of-focus points look more out of focus.
3. Your absolute focal length. Never mind that your 20mm on your micro four thirds camera has the same angle of view as a 40mm on a full-frame camera. The principle of similar triangles tells us that if infinity – i.e., the distance so far away for a lens that if it’s in focus, everything farther is in focus too – is 20 metres away at a given focal length, it will be 10 metres away at half that focal length. And similar triangles is also why it’s the relative, not absolute, aperture that matters. But see point 1: a smaller sensor means you’re seeing the image twice as close, meaning the circles that should be points are bigger.
4. The distance of the object from the camera. This is an extension of point 3: the smaller the distance to the camera, the smaller the distance between “too close to be in focus” and “too far to be in focus.”
The second important thing is the basic principle of focus in lenses, which is that focusing involves moving the lens itself towards and away from the sensor (or film), or producing the same effect with more complicated optics using multiple pieces of glass, and that to focus closer, you move the lens towards the object and away from the sensor. The stated focal length of a lens is its focal length at infinity; it gets longer as the subjects get closer. If you shoot large-format cameras, you know this very well: the lens racks forward on the bellows to focus closer. That means that you can make a lens focus closer by just adding an extension to it.
But adding an extension also puts the lens farther from the sensor or film, which means the image circle is actually larger, which means the sensor is getting less of it, which means your total light is decreased – and your effective f-stop is increased. So you have to compensate in your exposure, and macro extensions typically say by how many stops. But your depth of field is still getting thinner, because your object is getting closer.
An important entailment of the macro extension principle is that, since your extension effect is produced by relative increase in focal length, the same distance of extension will have more effect with shorter-focal-length lenses. If you have a 100mm lens and you add a 25mm extension to it, you’ve added 25% to the length. If you have a 50mm lens, you’ve added 50%. With a 24mm lens, you’ve more than doubled it. You’re focusing very close.
So. Let’s see how that works out. I have two macro extenders. The first is a sort of hybrid option: it’s a macro extender with lenses in it. I can adjust the focus and the relative extension. Here it is on the 135mm, focusing as close as I can.
It’s a long lens and it doesn’t focus all that close, so it’s way the heck across the table.
Here it is on the 50mm.
It can see quite close. Which also means the depth of field is rather less.
Now put it on the 28mm.
It’s nearly tripling the distance from lens to sensor on this one. So even though the angle of view is wider for the lens, the added length more than makes up for it.
But we can do still better than that! Just use a good old macro extension bellows attachment. I have one, made by Novoflex. Like most of the other stuff here, I bought it used, on ebay. But it doesn’t have a Canon FD mount. It has an L39 mount. Ah, what luck! I happen to have some L39 lenses: the 105mm f/3.5 that came with the bellows, a 50mm f/2 Russian one (Jupiter-8), and a 28mm f/2.8 Russian one (Industar-69). The Russian lenses aren’t the most contrasty lenses anywhere ever, or the sharpest either, but they will serve for demonstration purposes.
Here’s the 105mm one, all mounted up, racked out to full extension.
Here’s what it sees.
Here’s the 50mm.
Here’s what it sees.
Whoa! That’s part of the eye.
So now I bet you’re expecting a heck of a result with the 28mm, aren’t you? Tell you what, it focuses so close it gets in the way of the light source and it’s really hard to keep both camera and subject steady enough. The cat gives it the eye at less than full extension:
…and we see this:
Gah. Let’s replace the cat with that book there. It will hold steadier and be flatter and reflect more light.
We can rack it all the way.
Can you see what it’s looking at?
This. Notice how even the letter goes out of focus towards the edges? That’s how thin the depth of field is.
If you want greater depth of field, you can of course stop it down. You may even have a camera that does focus stacking – but only with native lenses, and that gets expensive.
I don’t often need to shoot portraits of individual letters, although I did do this picture of a grain of salt on a kitchen counter next to a nickel.
But normally I prefer things I can photograph hand-held with the clip-on lens. More the size of these grains of sugar.
One more thing. Obviously the pictures of my macro setup were shot with a different camera. Those of you who snoop a bit may have figured out that it’s a Sony α7 ii, which is a full-frame camera, whereas (as you can see) I took the macro photos with an Olympus E-PL3, which is a micro four thirds camera. Why would I do that when I could put those lenses on my Sony? Angle of view. The point of doing macro is to get as close as possible, which means as narrow an angle of view as possible. The Sony can crop down to the same angle of view, but at half the resolution (it’s 24 megapixels, which makes a crop to half the dimensions 6 megapixels, because a half by a half equals a quarter; the Olympus is about 12 megapixels). The depth of field is the same because it’s the same lenses. Also, the Sony shoots better hand-held in low light.
Macro photos taken with Olympus E-PL3 and the following lenses:
Canon FD 135mm f/2.5
Canon FD 50mm f/1.4
Canon FD 28mm f/2.8
Raynox Microscopic Lens M-150
Magnicon 3X Macro Auto Tele Converter
Novoflex Noflexar 105mm f/3.5
Jupiter-8 50mm f/2
Industar-69 28mm f/2.8
micro-4/3 adapters for Canon FD and Minolta mounts
Photos of equipment taken with Sony Alpha 7 Mark ii with Voigtländer Nokton Classic 40mm f/1.4 with M-mount adapter on the Sony for the Voigtländer lens
You can follow my latest collaborative project with James on Instagram at FotoLingo, a space where we combine our love for photography and words.
The same week James sent me this post, he also published this article in the BBC, made his regular post on Sesquiotica, and defended his Masters Thesis on phonaesthetics. The man is a writing inspiration. Congrats Harbeck!
This post adds to a growing series of posts where I share the talents and expertise of other photographers. You can see my interview with Maria Szemplinska, the first of this series.