Photography Technique: Focus Stacking

Macro Photography Focus Stacking 101

Depth of Field on Steroids for your Macro Shots

  • What is Focus Stacking?
  • Why do you want to use it?
  • When is an excellent opportunity to do it?
  • How do you do it?
  • What are the common pitfalls?
  • Software alternatives

What is Focus Stacking?

Focus stacking is basically merging/blending several images with different focal points. In post-processing, you use software to more or less automagically merge the in-focus parts into one image which then appears to have a greater depth of field than the original single images. It’s a bit difficult to put it into words, I’ll better show you what I mean.

Why do you want to use it?

We already touched on that above. If you are in a situation where you can‘t get enough depth of field with one shot only, either because the shutter speed is then too slow, or your maximum smallest aperture of your lens is still not small enough to get everything in focus, you can use focus stacking to still get everything in focus. It is a software solution to increase the depth of field by stacking the shallow focus planes of multiple images. It therefore increases the possible images you can create beyond the physical capabilities of your lens and camera combination.

When is a good opportunity to do it, and when should you avoid focus stacking?

There are several things you need to control to have a successful focus stack that ties in with the common pitfalls, so I’ll cover both in this paragraph.

How do you do it?

So how do you do the focus stacking? We have two phases, one is exposing the series of images, the other is the post-processing.

Shooting the image stack

You need to shoot a series of images, all identical apart from the focus point. How do you do that? Get your camera on a tripod. Then you want to decide if you focus with the focus ring of your lens or use a focus rail to change focus by changing the distance of your camera to the subject. If you do the latter, you know what to do: put your camera on the focus rail and turn off your auto-focus. And as your camera is on a tripod, turn off any image stabilizing (in body, or in-lens, or both).

Post-processing the images

Select your software tool of choice (see ‘Software Alternatives’ below), and load the image stack. Some programs do not allow raw files, so you have to convert the images before you can load them into the stack to process. If you have restricted computer resources and not much patience, you might also opt for using .jpg images, just because it is faster with smaller file sizes.

Software alternatives

I used Affinity Photo for my focus stack. Here is a tutorial video for how to do it (they call it ‘Focus Merging’):

Adobe Photoshop

Find a quick tutorial here about how that works in Adobe Photoshop:

Helicon Focus and Zerene Stacker

These two software packages are specialized on focus stacking. I haven’t used any of them yet, mainly because I do not use focus stacking very often, so I didn’t want to pay for another software package. But your use case might be different, so get a trial version and check them out.

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