Photographing Small Creatures with a Big Lens

Inevitably, many wildlife photographers will find themselves tempted by the allure of fast, exotic, super-telephoto lenses. These lenses offer unmatched optical capabilities, as long as you pay the price and carry the weight. But, as good as they are, most of these lenses have a hidden weakness: a disappointing close focus distance.

If you’re primarily photographing large mammals or bigger birds, this probably won’t be an issue. But if your subjects are hummingbirds, small reptiles, or even insects, you’ll quickly become aware of just how limiting that minimum focusing distance can be.

The inspiration for this article came from my recent experience photographing one of the world’s smallest hummingbirds, the Gorgeted Woodstar (Chaetocercus heliodor). This bird measures just about 60mm in length. Its body, barely tipping the scale at two grams, is carried aloft by wings with a span under 35mm. A true miniature even among hummingbirds.

In some sense, photographing this bird isn’t especially difficult because it’s usually not very shy. Its flight resembles that of a bumblebee, which moves between flowers in a seemingly clumsy and fairly predictable way. But with a large, fixed telephoto lens, the insufficient minimum focusing distance can make it almost impossible to fill the frame with this fascinating bird.

To understand the challenge, let’s take a closer look at the specifications of some of today’s fast supertelephoto lenses. The key factors here are focal length and minimum focusing distance, which will result in a particular maximum magnification.

Nikon Z 400mm f/2.8 TC VR S

• Minimum focusing distance: 2.5m
• Maximum magnification: 0.17×

Nikon Z 600mm f/4 TC VR S

• Minimum focusing distance: 4.3m
• Maximum magnification: 0.14×

Sony FE 400mm f/2.8 GM OSS

• Minimum focusing distance: 2.7m
• Maximum magnification: 0.16×

Sony FE 600mm f/4 GM OSS

• Minimum focusing distance: 4.5m
• Maximum magnification: 0.14×

Canon RF 400mm f/2.8 L IS USM

• Minimum focusing distance: 2.5m
• Maximum magnification: 0.17×

Canon RF 600mm f/4 L IS USM

• Minimum focusing distance: 4.2m
• Maximum magnification: 0.15×

Looking at these numbers, it might seem that you are better off with a 400mm lens that has a shorter minimum focus distance. But maximum magnification is the really important statistic, and that hovers around the same (disappointing) value of about 0.14× to 0.17× regardless of the lens. This means, on a full-frame camera, we are only filling the frame with a subject that’s about 24 cm or 9.4 inches in size.

This problem is not universal in telephoto lenses – it’s only common in the exotic and very expensive ones, for some reason. Some telephoto lenses have great close focus capabilities, especially a lot of zoom lenses. The Nikon Z 180-600mm f/5.6-6.3 has a reasonably good 0.25× magnification. The Canon RF 100-500mm f/4.-7.1L has an impressive 0.33× magnification.

This is often a true benefit for the less expensive telephotos. With a small subject, it is photographers with the costly 400mm f/2.8 or 600mm f/4 lenses who will be jealous of their friends with a 100-400mm or 200-600mm lens.

So, what do I do when shooting with my Nikon AF-S 500mm f/4E, a lens whose maximum magnification is a paltry 0.15×? The first option is to use a teleconverter. The second option is to crop the photo – either by cropping in post-processing or by using a crop-sensor camera (or both).

To calculate how small of a scene you can capture with your equipment, simply divide the width of your camera sensor by the magnification found in your lens’s specifications. For example, using a 36 millimeter wide full-frame camera sensor, a lens with (say) a magnification of 0.2× can fill the frame with something that is 36/0.2 millimeters across. This calculates to 180 millimeters (or 7.1 inches). If your subject, like the Gorgeted Woodstar hummingbird, is about 60 millimeters across, that means it would fill approximately one third of the frame with such a lens.

If you use a smaller camera sensor, the math is a little more in your favor. With an APS-C sensor of 22 millimeters wide, the same lens could fill the frame with something 110 millimeters wide (4.3 inches), much better than the 180 millimeters you could achieve on full-frame. However, you also need to take the camera’s resolution into account. A 20-megapixel APS-C camera, like Nikon’s Z50 II, puts the same number of pixels on a distant subject as a 45 megapixel full-frame camera. But something like Canon’s 32.5-megapixel EOS R7 could only be matched by a (nonexistent) 85 megapixel full-frame camera, so it has a real advantage in these situations.

A teleconverter helps, too. It doesn’t just increase a lens’s focal length but also its magnification. For example, a magnification of 0.2× on the bare lens becomes a more respectable 0.28× with a 1.4× teleconverter, and a very impressive 0.4× with a 2× teleconverter. I’ve said it before, but I really enjoyed using the built-in teleconverter on Nikon’s 400mm f/2.8 TC VR S and hope that this feature makes its way into less expensive lenses one day.

So, does it make sense to use exotic super-telephotos on APS-C bodies for small subjects? Honestly, with Nikon at the moment, the benefit is not really there, since their highest-resolution APS-C camera is 20 megapixels. I would rather shoot with the 45-megapixel Nikon Z8 or Z9 and crop afterwards. It’s easier to keep the subject in the frame, and you’ll have more room for composition adjustments in post. Most importantly, the image quality and number of pixels on your subject will be virtually the same. The story would be different if you shoot with one of the higher-resolution APS-C cameras available from Fuji or Canon.

And I would like to bring up one other point, something else you can do when the close focusing distance on your lens is not sufficient: be more careful and creative with your composition. Consider including more negative space around a smaller subject. Or, find other elements in the environment to fill the rest of the frame with something interesting.

So, let’s circle back to the central question of this article: does it make sense to photograph very small subjects with big lenses? It’s something I find myself pondering in the field quite often. And whenever I do, I’m reminded of a scene from a (typically) Czech stage play called Blaník. In it, two knights face off in a duel – one sentenced to execution, the other tasked with delivering it. The executioner is given almost comically short sword. The condemned gets a two-meter-long monster of a blade. I won’t spoil how that duel ends, but the play’s recording is available here if you’re curious.

What sticks with me is what the smaller-sworded knight says mid-fight as he evaluates his weapon: “You know what? I’m actually glad I’ve got this short one. It’s nimbler. Easier to handle.” And that, really, is how it goes with lenses too.

Sometimes the best fix isn’t the most expensive one. If you’re aiming to photograph small subjects, it can be done with an exotic supertelephoto, but only with some compromises. Instead, the best option is a zoom like a 100-400mm or 200-600mm lens, and it will also be easier on your wallet.

So personally, I recommend photographing small creatures with a small lens. The benefits of a fast supertelephoto prime are outweighed for these subjects. You are less likely to need the fast aperture (note f/13 in the photo above), you will want to be more nimble to position the camera properly, and most of all, you will appreciate the shorter minimum focusing distance.

If all you have is a 400mm f/2.8 or 600mm f/4 lens, go ahead and use a teleconverter and crop, and you will likely get reasonable results. But there are times when the less expensive lens pays off (in more ways than one), and this is the perfect example.