Medium format lenses DOF

What is the DOF for (True 645 and cropped 645)

 

400mm F2.8

80mm F2.8

300mm F5.6

165mm F4

 

in 35mm FF?

There is no single answer to this. It depends on the subject distance and taking aperture, as well as the format size. It also depends on which focal length(s) you choose as being eqivalent between formats that have a different aspect ratio.

 

Which particular cropped "MF" sensor?

 

There's a neat online DoF calculator here.

 

It shows that a 50mm lens at f/1.8 on 35mm is roughly equivalent to an 80mm lens @ f/2.8 on 645 with a subject distance of 3m, but your question is too vague to know if this is the kind of answer you're looking for.

Edited July 25, 2017 by rodeo_joe|1

For a rough result you could multiply focal length and aperture with the crop factor but a DOF calculator is superior.

Another interesting factor that comes into play in all of this is how software has been developing and improving over the years. I firmly believe that we need to not only look at a camera body and related lenses as a ‘system’, but also the software that we use with it. Advances in software are enabling higher levels of imaging performance that we ever thought possible, regardless of the gear a photographer chooses to use.

That online calculator is awesome !

 

caseyhause: Not sure how software plays into DoF. Can you explain?

I am not sure what the above comment on software meant, but, with enough signal, you can do deconvolution and sharpen up an image.

 

My favorite reference is what was done with Hubble telescope images with the original lens system. The point spread function was very accurately known, such that deconvolution wasn't so hard to do.