What is focus bracketing and why use it?
At macro distances the depth of field is extremely shallow – often just a millimetre or two. That means only a thin slice of your subject is sharp in any single frame, no matter what aperture you use. Focus stacking solves this by taking multiple frames each focused at a slightly different point, then blending them into one fully sharp final image in software.
Focus bracketing is the shooting step of this process. Your Canon camera automatically fires a sequence of frames, shifting focus slightly between each one. You then take those frames into software like Helicon Focus or Zerene Stacker to merge them into the final image.
One important distinction: Canon cameras do focus bracketing but not in-camera focus stacking. They capture the sequence and save each frame individually as a RAW file. The blending happens on your computer afterward. This is actually the preferred workflow for most serious macro photographers since it gives full RAW quality and complete control over the merge. For a full overview of the technique, the best Canon cameras for focus bracketing guide covers the camera options in detail.
Before you start: what you need
- An autofocus-compatible lens with full electronic communication — native RF lenses work best; adapted EF lenses work via the Canon EF-EOS R adapter; fully manual lenses will not work
- A stable tripod — any camera movement between frames creates misalignment that software struggles to correct
- A remote shutter release or 2-second self-timer to avoid vibration when triggering the sequence
- IS turned off on the lens — image stabilisation can introduce micro-vibrations between frames that cause ghosting artefacts in the merged image
Canon RF mirrorless cameras
The RF lineup shares the same focus bracketing system across all models. The menu location varies slightly — on the R5 and R3 it sits deeper in the menu structure, while on the R7, R8, and R10 it is usually accessible more quickly. The settings themselves are identical.
Press the Menu button and navigate to the Shooting menu (red camera icon). On the R5 and R5 Mark II look in Shooting Menu 7. On the R6 Mark II and R6 Mark III look in Shooting Menu 7. On the R7 and R10 look in Shooting Menu 5 or 6. On the RP look in Shooting Menu 6. Scroll through until you see Focus Bracketing.
Select Focus Bracketing and set it to Enable. The sub-menu will expand to show the bracketing settings below.
This is how many frames the camera will fire. For a medium mushroom at moderate magnification, 15 to 30 is a good starting point. For very small subjects at high magnification you may need 50 to 100 or more. Start at 20 and adjust based on results. The camera will stop automatically once it reaches the set number or the furthest focus point, whichever comes first.
This controls how much focus shifts between each frame. It is set on a scale of 1 to 10 — 1 is the smallest step, 10 is the largest. For true 1:1 macro work start at 1 or 2. For closer subjects or higher magnification use 1. For larger subjects at lower magnification you can go higher. If your merged image shows gaps in sharpness, the step is too large. If many consecutive frames look identical, increase it.
If your model shows an Exposure Smoothing option, turn it on. As focus shifts from near to far the lens aperture changes slightly, which can cause brightness variation across the sequence. Exposure smoothing compensates for this automatically, giving more consistent frames for the stacking software to work with. Available on R5, R5 Mark II, R6 Mark II, R6 Mark III, R7. Not available on all models.
Use Aperture Priority (Av) or Manual (M) mode. For focus stacking shoot wider than instinct suggests — f/5.6 to f/8 is a good starting range. Stopping down past f/11 introduces diffraction which softens the image and defeats the purpose of stacking. The aperture and diffraction guide explains the reasoning fully.
Autofocus on the nearest point of your subject. The camera fires from nearest to furthest focus automatically. Trigger with a remote shutter release or 2-second timer. Do not touch the camera during the sequence. On the R5 and R7 the sequence fires at full burst speed — the whole thing takes just a few seconds for a 20-frame stack.
Canon EOS 90D (DSLR)
The 90D uses a slightly different menu structure from the RF mirrorless lineup but the concept is identical.
Press Menu and go to Shooting Menu 3. Scroll down to find Focus Bracketing and select Enable.
Same logic as the RF cameras. Start at 20 shots and focus increment 2 for macro work. Adjust based on results.
The 90D does not have exposure smoothing, so shoot in Manual (M) mode with a fixed aperture, shutter speed, and ISO. This keeps brightness consistent across the stack and makes merging easier.
Switch to live view, zoom in to your subject, and manually confirm focus is on the nearest point before starting the sequence. Trigger with a remote shutter release.
Recommended settings for macro photography
These are starting points based on common macro scenarios. Adjust based on your specific subject and magnification.
For more on pushing magnification beyond 1:1, the extension tubes and Raynox DCR-250 guide covers the options. And for understanding why wider apertures produce sharper stacks, the aperture and diffraction article covers all the detail.
Processing the files afterward
Once your sequence is shot you have a folder of RAW files numbered sequentially. The workflow from here:
Option A — Direct to Helicon Focus: Open Helicon Focus, drag in your RAW files in order, select Method C (weighted average) as a starting point, and run the stack. This is the fastest route and what most photographers use. The full workflow is covered in detail in the Helicon Focus guide.
Option B — Lightroom first, then Helicon Focus: Import into Lightroom, apply any exposure or colour corrections consistently across all frames using Sync Settings, then export as TIFF or DNG and open in Helicon Focus. This gives more control over the individual frames before merging but adds time to the workflow.
Option C — Photoshop Auto-Blend Layers: Load frames as layers in Photoshop, select all layers, and go to Edit > Auto-Blend Layers > Stack Images. Works reasonably well for simple stacks but Helicon Focus handles complex stacks significantly better.
Troubleshooting common problems
Focus bracketing is greyed out in the menu
The lens may not be communicating electronically with the body, or the camera may be in a mode that disables bracketing (some drive modes or custom shooting modes can block it). Check you are using a compatible AF lens, that the camera is in a standard shooting mode, and that no custom function is overriding the menu.
The merged image has gaps — areas that are not sharp
Your focus increment is too large. Reduce it by 1 step and reshoot. Also check whether the subject moved between frames — wind is the most common cause on outdoor stacks.
The merged image has ghosting or double edges
Usually caused by camera movement between frames, IS being left on, or a subject that moved. Make sure the tripod is solid, IS is off, and you are using a remote shutter release. If shooting outdoors, wind on the subject itself can also cause this — early morning in still air is the best time for outdoor stacks.
Brightness varies across the stack
On the 90D or any model without exposure smoothing, shoot in Manual mode with fixed settings. On RF bodies make sure Exposure Smoothing is enabled.
The sequence stops before reaching the full number of shots
The camera stops automatically when it reaches its furthest focus point, even if the set number of shots has not been reached. This is normal — it means the camera covered the full focus range before completing the count. Your stack is complete.
For further reading on the full mushroom photography workflow using focus stacking, the top tips for mushroom photography article covers technique, lighting, and composition alongside the technical side. And for choosing the right Canon camera for this work, see the best Canon cameras with focus bracketing guide.
Best of luck out there.