Shooting with a wide aperture has its benefits: lovely bokeh, brighter images with a faster shutter speed in low light. However, the inherently shallow depth-of-field can also make it hard to get subjects fully in focus. One solution: in-camera focus bracketing and depth compositing function on the latest EOS R system mirrorless cameras! We show an example using macro and close-up photography, but this also works for capturing detailed images of dimly lit interiors, (Reported by Chikako Yagi, Digital Camera Magazine)

EOS R7/ RF100mm f/2.8L Macro IS USM/ FL: 100mm (160mm equivalent)/ Aperture-priority AE (f/2.8, 1/200 sec)/ ISO 100
Composited from 30 focus-bracketed shots

Focus bracketing and depth compositing helped keep this mushroom fully in-focus while preserving the creamy f/2.8 background blur.

 

The depth-of-field dilemma in close-up photography

It’s fascinating to see objects close-up through a macro lens, but getting a well-exposed shot of it that also looks fully in focus can require more effort than expected!

One reason for this is the extremely shallow depth-of-field (DOF) during close-up photography. A shallow DOF is what creates the beautiful background blur (bokeh) that is so desirable in portrait photography, but it can also cause subjects to look "blurred" or "not sharp" if they are too out of focus. Yet, using a narrower aperture to increase the DOF might not achieve the desired effect.

f/2.8: What (usually) happens with a wide aperture setting

EOS R7/ RF100mm f/2.8L Macro IS USM/ FL: 100mm (160mm equivalent)/ Aperture-priority AE (f/2.8, 1/200 sec)/ ISO 100

A wide aperture setting like f/2.8 results in a shallow DOF, and close-up shooting makes it even narrower. While there’s a lovely background bokeh effect, only a small part of the mushroom is in focus, making the overall image look very soft.

f/22: In-focus subject, busy background

When we narrow the aperture to f/22, the DOF becomes large enough to put the mushroom fully in focus. However, there are a few trade-offs:

- The background is less blurred out, which makes it more distracting.  
- Under low-light conditions, the image might become too dark. You might have to use a slower shutter speed, increasing the chances of camera shake in handheld shots.
- Your images could still end up soft due to diffraction blur.

 

Solution: Focus bracketing + depth compositing

EOS R7/ RF100mm f/2.8L Macro IS USM/ FL: 100mm (160mm equivalent)/ Aperture-priority AE (f/2.8, 1/200 sec)/ ISO 100
Composited from 30 focus-bracketed shots/ Focus increment: 1

Small subjects like this mushroom require fewer shots and a smaller focus increment setting to become fully in focus, especially from this relatively flat shooting angle.

 

What are focus bracketing and depth compositing?

Focus bracketing involves taking multiple shots with different parts of the subject in focus. When these shots are combined (“focus-stacked” or “depth-composited”), the resulting image has a larger DOF than is ordinarily possible.

Older cameras such as the EOS RP and PowerShot G7 X Mark II have a function that automates focus bracketing by taking multiple shots in rapid succession. Newer cameras such as the EOS R7, EOS R10, and EOS R50 can also stack the images in-camera so that you can see the results immediately without waiting until you get to a computer to blend them.

 

Step-by-step: How to use focus stacking and depth compositing

The settings for the next two steps depend on your subject. You might need a few trial runs to find the best results for the scene.

3. Set the focus increment

This sets how much the focus is shifted for every shot. The camera automatically adjusts the focus position to suit the aperture setting. The combined depth of field is the largest with a narrow aperture setting (high f-number). The focal length and lens can also affect the final result.

4. Set the number of shots

For small subjects such as the mushroom in the examples above, 30 shots with a narrow focus increment of “1” at an aperture setting of f/2.8 should be enough to get the entire subject in focus while leaving the background blurred. The background bokeh might end up looking strange if the focus increment is too wide. Of course, if you are using this function to deep-focus a scene from the foreground all the way to the background, your settings would be different.

To check: Does your memory card have sufficient space?

The focus-bracketed shots are recorded in your usual recording format. If you’re shooting RAW files, make sure you have enough remaining storage space!

7. Create a new folder if necessary

The icon in the red box lets you create a new recording folder so you can separate your focus-bracketed and focus-stacked images from normal shots.

8. Place the focus point at the front of the image, wherever you want the in-focus plane to start.

Then fully press and release the shutter button. The camera will take the specified number of shots, shifting the focal position accordingly. If “Depth composite” is enabled, it will automatically combine the shots into one JPEG image.

 

Things to note when shooting

- Compose with extra allowance.
The shots might be cropped for alignment during the compositing process.

- Don’t use this on moving subjects. Hold the camera still.
This increases the chances of success.

- When shooting under artificial lights, set the shutter speed to prevent banding.
The anti-flicker function is unavailable as the focus bracketing function uses the electronic shutter. You will need to find a shutter speed setting appropriate for the light source’s flicker frequency. 

Most of the time, this frequency (cycle) should be the same as that of the alternating current (AC) in your country. For example, if your country uses 50-hertz cycles, try 1/50 or 1/100 seconds. If that doesn’t work, the light source might have a different flicker cycle, so take a few test shots at other shutter speeds in electronic shutter mode.

 

In-camera focus bracketing and depth compositing helps in landscape photography and wide-angle shooting situations too! It reduces the usual workflow described in the article below:
A Guide on Focus Stacking for Tack Sharp Landscape Shots

For more macro and close-up photography tips, see:
Mouth-watering Macro: The Art of Close-up Food Photography
Macro Photography Technique: Creating the Illusion of Space and Depth
Lens FAQ: What Images Can I Get with 0.25x or 0.5x Magnification?