Focus Bracketing R6

Started 3 months ago | Questions thread
JustUs7 Senior Member • Posts: 2,664
Re: Focus Bracketing R6
1

The increments are more about focal plane overlap than actual measurements. 1 meaning significant overlap of the depth of field requiring more images. 10 meaning almost no overlap.

The camera calculates the depth of field based on aperture, focal length, and distance from the initial focus point. So, shooting at 24mm at f/8 using an increment of 10 and an initial focal point 5 ft away might only require 2 or 3 images to cover a focus bracket to infinity. While focusing at the minimum focus distance using a 100mm lens at f/2.8 using and increment of 1 could take hundreds.

I generally leave it at 4, which I guesstimate to be about 60% overlap then base my number of images using a depth of field calculator. If the calculator says my depth of field is 0.2 inches, and I need to cover a 3 inch subject, I’ll take images and stack as many as I need to cover the subject. My math says 40, but I’ll review and leave off wherever I no longer need sharp images. So I might take 60 just to be safe and delete what I don’t use.

For the 3 inch subject with a 4 overlap factor, my math goes something like 0.2 * (1 - 0.6) = 0.08 inches. I have 0.08 inches that doesn’t get covered by overlap. 3 / 0.08 = 37.5 images. Then I add a few for a fudge factor.  With a lower number, I need more images.  With a higher number, less.

Remember too that as your focus point moves through the scene, the distance from the sensor becomes greater and therefore depth of field increases. This means that regardless of number (1-10), the focus increment will be variable (increasing) as it moves through the scene. There won’t be a fixed distance to assign.

Or if I want to go to infinity, I’ll put in 999 images and the camera stops when focus reaches infinity.

 JustUs7's gear list:JustUs7's gear list
Canon EOS 1000D Canon EOS Rebel SL1 Canon EOS RP Canon EOS M6 II Canon EF 75-300mm f/4.0-5.6 III +7 more
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