How to use focus stacking to capture greater detail

It's arguably the biggest problem in macro photography: you get close to your subject and typically select a wide aperture to capture as much light as possible, but as a result the depth of field becomes very narrow, leaving much of your image out of focus. Whether you're shooting macro images of tiny insects or a wide expanse of landscape, sometimes you crave a greater depth of field than one shot with one lens can provide. Simply closing down to a small aperture may not give enough sharpness throughout the frame, particularly when shooting macro. That's where focus stacking can help.

To create focus-stacked images, you start by bracketing a number of images of the same subject with slightly different parts of that subject in focus. Those images are then blended together, or 'stacked', in post-production to produce a single image that has greater depth of field, with the subject in focus throughout the frame. It's a great way to transcend a lens's natural limits and create images that are extraordinarily sharp and detailed throughout.

But how exactly do you take and blend focus-stacked images successfully? How does the technique differ when shooting landscapes rather than macro, what is the best kit to use, and how do you turn a succession of shots into one detailed image? Here, Canon Ambassador and nature photojournalist Christian Ziegler, macro specialist Matt Doogue and landscape and travel photographer David Clapp share how they use focus stacking to create detail-rich shots.

1. Close-up portraits of insects

Matt Doogue began photographing insects and arachnids seven years ago. He has refined his focus stacking technique to overcome extremely narrow depth of field while shooting small subjects at high magnification. He typically uses a Canon EOS 6D (now succeeded by the Canon EOS 6D Mark II) paired with a Canon MP-E 65mm f/2.8 1-5x Macro or Canon EF 100mm f/2.8L Macro IS USM lens, for their wide apertures and magnification factor.

"Most people think that by using very small apertures you'll get more of the subject in focus," he says. "That's correct, but that's also going to cause diffraction, where light disperses and image sharpness is reduced, and your exposures are much longer.

"Shooting at wide apertures such as f/2.8 avoids diffraction and allows me to let more light in, so I can use shorter exposures. However, if I'm shooting a spider at 5x magnification on my 65mm macro lens, I will get only the two front eyes in focus and the rest is completely blurred. Focus stacking allows me to bring that whole face in focus to get an amazing portrait."

2. Highlighting macro details in nature

Christian Ziegler recently used the focus stacking technique for a series of images of flowers and plants, taken in Scotland on his Canon EOS-1D X Mark III with a Canon EF 100mm f/2.8L Macro IS USM lens.

"I rediscovered focus stacking during the Covid-19 lockdown, while we have all been stuck at home," he says. "I used this technique maybe 15 years ago in Panama for flowers, but it was much more complicated back then. Now, post-processing is so simple that it's easy to take some images, play around and see if it works.

"I spent a lot of time documenting the onset of spring. I especially love spring flowers and young leaves. I collected many species and brought them back to my studio to play around with them – taking multiple images and then stacking them to create a perfectly sharp image. I think this technique works really well for natural details such as flowers, seed heads and insects. I wanted to show the beauty and delicate nature of these subjects."

3. Shooting outside: focus stacking for landscapes

Focus stacking post-processing methods

Some Canon cameras such as the Canon EOS R5, Canon EOS R6, Canon EOS RP and Canon EOS 90D feature built-in automatic focus bracketing, to make capturing your focus stacking images even easier. This enables you to set the camera to shoot the desired number of images at selected focusing increments. The camera starts focus bracketing from the nearest point and works towards infinity. The wider the aperture, the more gradual the focus increments and the greater the number of shots.

Once they've captured their component images, the three photographers have different ways of creating their final stacked images, using either general image editing software or dedicated focus stacking programs. However, their post-capture process is broadly similar: the shots that give the widest range of focal points are selected and edited; then, they are aligned and blended into one composite image, with any anomalies removed (such as an insect's leg that has moved between exposures in Matt's work).

Canon's Digital Photo Professional (DPP) software, a free download for owners of Canon EOS cameras, is the perfect tool. Version 4.10 and newer include a Depth Compositing function, which is compatible with images taken with cameras that feature focus bracketing along with the Canon EOS R, Canon EOS RP and Canon EOS 5D Mark IV. This function enables images to be automatically adjusted in certain ways, for example smoothing the compositing boundary. The output image can be adjusted using the Depth Compositing Editing tool to ultimately produce a single perfectly focused image.