Focus stacking for macro

In macro photography, depth of field is a real issue, but Rod Lawton shows how focus bracketing and Photoshop can fix it

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In regular photography, shallow depth of field is often a valuable creative effect. Portrait photographers use it to blur backgrounds but keep their subjects sharp, for example. But in macro and close-up photography, depth of field can be a problem, simply because you can't get enough of it.

At very close focusing distances, the depth of field becomes progressively more shallow, so it becomes difficult to keep the full 3D shape of an object sharp, even at a small lens aperture. You can focus on the front, you can focus on the back, but you can't get them both sharp at the same time.

This is where 'focus stacking' comes in. This is a technique used widely by macro photographers where you take a whole sequence of identical shots of your subject, but with the focus shifted slightly each time. The aim is to get a sequence of shots where every part of your subject is sharp in one of these shots.

This stage is 'focus bracketing'. Many cameras have a focus bracketing mode built in, including the Canon EOS R8 used for this image. With the EOS R8, you choose the number of shots you want to take and the focus shift for each one, and the camera captures the sequence automatically.

'Focus stacking' is the phase where you merge these images together, and while some cameras can do it for you, the results will generally be better if you merge your focus brackets in software.