Working with the working distance

How close will the front of the lens get to the subject?

The focal length you choose can affect the image in a number of significant ways, one of which is the working distance. This is the measurement from the front of the lens to the subject when the lens is set to its minimum focusing distance.

A longer working distance can be an asset when it comes to photographing small creatures, as they are less likely to be spooked. You’re also less likely to be close enough to cast a shadow over the subject, although Canon’s shortest macro lenses have built-in Macro Lites to compensate for any potential loss of light.

Longer macro lenses give you more room to work with. Compare the EF-S 35mm f/2.8 Macro IS STM and the EF 100mm f/2.8l Macro IS USM, for example. Both lenses give you a 1:1 reproduction ratio when they are set to their minimum focusing distance, but the 35mm lens has a working distance of just 30mm at this magnification, with the 100mm lens offering a working distance of 14cm. This means that you can be around 14cm away from the subject with the 100mm lens, while still getting that life-size photographic image size on camera.

The EF 180mm f/3.5l Macro USM allows you to get a 1:1 reproduction ratio from even farther away – around about 25cm – but with a price tag north of £1000, it will set you back quite a bit in financial terms, as well as in working distance, however.

Focal length also affects the field of view, or how much of the whole scene is captured by the lens. Longer focal lengths give a narrower field of view that records a smaller section of the background, which can help to make a subject stand out that bit more.