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This is a 5 shot stack. Notice the teensy tiny little insect on the far left petal |
The EOS R5 has a feature called [Focus bracketing] which can be found in the Camera [red] menu > screen 5. Why it is not allocated to the AF menu I have no idea.
The idea is to make a series of exposures each at a slightly different focus distance covering the nearest and most distant relevant parts of the subject. These are later blended in an image editor to form a single image hopefully with all required parts of the subject in sharp focus.
This post will describe the use of Photoshop but there are other programs available.
The traditional method of achieving great depth of field is to close down the lens aperture, to f22 if necessary. This is effective but there is some sharpness loss at f22 due to diffraction at the lens aperture diaphragm and there could be some subjects which cannot be covered by f22.
Subject selection
I find that close-ups are suitable particularly where there is clear separation between subject and background.
Some types of landscape are also suitable however I have found that when there is fine foliage in the background the blending process in Photoshop does not work well. In some cases the result is just a blurred mess.
Lens
To date I have only used the RF50mm f1.8 and the RF 35mm f1.8. Both these lenses exhibit considerable “focus breathing” which is a change in effective focal length with focussing. As a result each frame of the focus stack renders the image a different size which makes hard work for the blending programme.
It may be that a lens with no appreciable focus breathing could be more suitable, I just don’t have a suitable one at present.
Tripod
I have read reports of some users getting decent results hand held but my experience is that mounting the camera to a tripod makes the job a lot easier and better results more likely.
Wind
Outdoors, wind is the enemy. I find it difficult to get acceptable results unless the subject is perfectly still.
Preliminary tests
I suggest you run tests to discover whether focus stacking gives a perceptibly better result than simply closing down the lens aperture. The single shot approach is much easier both at the capture stage and at the image processing stage. A sharply in focus background may not enhance the image at all.
Setting up the camera
* Set Focus bracketing to Enable.
* Number of shots. There are no definite guidelines for this, you will have to experiment. Bear in mind that the R5 produces big files (reduce file size by shooting CRaw or JPG) which give the computer a lot of work to do. If you go overboard with 20 shots the computer could take forever to process them. I generally aim for 5 shots and test.
* Focus increment. There are no rules. I start with a setting of 6 and experiment.
* Exposure smoothing, enable.
* Lens aperture. Try f8-f11 and test.
* I set Av, ISO 100, IS off, CRaw, 1 point or spot AF method, 2 sec timer delay.
Capture process
Select a subject, mount the camera on tripod at an appropriate distance from the subject, frame up and check the composition.
Touch the screen to focus on the closest part of the subject which is required to be sharp.
Press the shutter button. The camera will make the sequence of exposures at increasing focus distances. E-Shutter is used.
Playback the first and last frames of the sequence to check that you have the near and far parts of the subject sharp.
If desired you can ignore the [Focus bracketing] function and make a sequence of exposures each focussed manually at a different distance. Make sure they all have the same exposure.
Post processing
If you used Raw or CRaw capture select all the files in Bridge and open them in Adobe Camera Raw. Then select all and go to Optics>Profile>Remove chromatic aberration and Use profile corrections.
Now open all the files in Photoshop and go to File>Scripts>Load files into stacks, use open files, attempt to auto-align.
See each file load onto a different layer and select all layers.
Go to Edit>Auto-blend layers, seamless tones and colors.
The computer will obey your command, fairly quickly if there are few files, very slowly if there are many files, and produce a blended picture.
Go to Layer>Flatten image.
Then further refine the composite image in Photoshop or (recommended) select Filter> Camera Raw and make adjustments in that program.
Save when finished.
Compare the focus stacked version to your f16 and f22 versions to determine if stacking delivered an advantage.
Summary
Focus bracketing in camera and stacking in Photoshop works and can with some subjects deliver a more pleasing result than simply closing down the lens aperture.
Considerable experiment is required to achieve best results.