DOF and Cropping take 2

Started Feb 11, 2014 | Discussions thread
awaldram Forum Pro • Posts: 12,741
Re: DOF and Cropping take 2

moving_comfort wrote:


On the same format.Did you leave that part out on purpose? Has anyone tried to say that's not the case?

By the way, are you still trying to claim that cropping FF and displaying at the same size as before does not change DOF, or have you moved on to something else? I'm confused about what point you're trying to make with that link.

I refer you to my first post in this thread, I think maybe it you that's skipping stuff as I clearly point out that magnification is relative to both sides , Standard vewing or sensor hence why Ians reference and Cambridge in color and Myself are saying essentially the same thing.

"This is nothing different to what I've been saying or Cambridge in color for that matter if your using the longer focal length to deliver greater magnification on larger sensors the the DoF will alter i.e you will need to shrink the aperture."

Hence why "at the same image size" is critical and why "cropping FF and displaying at the same size as before does not change DOF" is true

It makes no odds if your Zoom, Crop or use a magnifying class if your representing the target at the same size the DoF will also be the same, Look at James algorithms and see.

Ian's source says exactlly the same

"This is because larger sensors require one to get closer to their subject, or to use a longer focal length in order to fill the frame with that subject."

This is about maintaining image size to what it was before


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