How can I calculate the depth of focus (Depth of field, DoF) for video recording?
There are some tools around that calculate the DoF for different camera types depending on focal length, f-stop and subject distance, e.g.
My assumption is, that the DoF for video recording is bigger than that for photographs, because video is recorded with lower resolution, and therefore a higher degree of unsharpness can be accepted without visible effect.
My idea was to calculate the size of a single pixel and use this size as "circle of confusion" parameter.
My question: Are these assumptions and the example calculation below correct? What is a reasonable way to calculate DoF for video?
- Canon EOS 600D / Rebel T3i
- object distance 2m
- recording format 1080p
From the 600D's sensor size (22.3 mm x 14.8 mm) and video resolution (1920x1080) I calculate the pixel size to be 0.0116 mm x 0.0116 mm, or 0.016 mm in diagonal.
Entering these numbers into dofmaster, I get 1.6 m as a result (1.48 m ... 3.08 m).
What surprises me is, that using the camera model directly instead of the CoC, the result is 2.02m, which is bigger than that vor video.
Accordingly, when calculating for a video resolution of 720x576, I get a DoF of 146m.