Focus stacking for macro photography

Want better pics of close-up subjects? There’s a simple technique called focus stacking for macro photography.

One of the problems you’ll likely encounter in macro photography is encompassing the entire subject of your image with sufficient depth of field when close focusing. If you’re shooting a tiny insect at close range, for example, you can capture its head or its abdomen in minute detail, but not both at once (or anything in between). Using a narrow aperture to increase depth of field doesn’t solve the problem and can even make things worse (diffraction, lack of luminosity).

Focus stacking is the solution. It’s a simple trick that let’s you blend together a series of shots of a subject taken at various focal zones in succession, generating a single composite macro image with each in-focus segment neatly aligned from stem to stern to achieve dazzling results. It’s a multi-step process in two separate stages: pre- and post-production. Here’s how it works.

Stage 1: Capturing your shots
Depending on your subject, you’ll need to get up to 20 sequential images (sometimes more) at different focal planes along its length, and this can be done in two ways: automatically (with built-in camera function) or manually (the good old-fashioned painstaking method).

Thankfully, there’s a wide range of recent models to simplify things with an in-camera focus stacking mechanism, including the Fujifilm X-Pro 3 and X-A5, the Nikon D780, the Olympus OM-1 and many others. Just set your parameters, compose the shot and press the shutter button. Your camera does all the heavy lifting.

When doing this manually, it’s a good idea to use a tripod to help keep the composition perfectly aligned throughout the shoot. Set your camera to manual mode, choose your desired exposure setting (something in the range of f/5.6 to f/8 is ideal) and a preset white balance to maintain consistency, as well. Switch the lens to manual focus and decide whether you’d like to begin with the foreground or the background (doesn’t matter which), focus manually on that spot and take your first shot.

Moving forward or back, depending on the approach you’ve taken, find your next zone of focus and adjust the lens incrementally to set up the next shot. (If you really want to nail it with total precision, consider using a macro focusing rail.) Repeat until you’ve fired off enough shots and feel satisfied with the number of images you’ve collected.

Stage 2: Blending your shots
If you know your way around Photoshop and other similar editing suites, this is actually the easiest part. Whether you have a small handful of images to choose from or up to 20 or more, examine them closely and be selective about which ones should make the final cut. Make sure that things like exposure, highlights and shadows are consistent throughout.

Drag each chosen image into a single document using the Open in Layers option, then select the Auto-Align Layers tool to ensure that they’re all lined up properly. Next, use the Auto-Blend Layers tool to work its magic. At this point, you can also adjust the overall tone and colour of the final image.

In the last step, just double-check for minor inconsistencies and imperfections that you can adjust manually and, voilà, you’re done. In an instant, you’ll see that it was worth the extra time and effort to end up with a crisply detailed, nicely resolved macro image that the camera couldn’t have achieved on its own without your careful attention.

Cover Image Credit: RoonZ nl