Some of you people are very knowledgeable when it comes to optical science.
So, I would like to ask you this:

On the internet there is an ongoing discussion about this subeject.
Some say, that smaller formats have greater DOF (Photonet). They say that in
order to get comparable images, I must use shorter focal length to go with
the smaller format, thus achieving greater DOF. They are using circle of
confusion (COF) theories to support their point of view.

I (and Photozone) say, that smaller formats only show a part of the image,
captured by a specific focal lenght. If I shoot the same scene twice with
the same camera, same lens (focal length( and same aperture and focus point,
you will get identical images on let's say APS and 35mm film - that is for
the part, that is covered by the smaller format (e.i. APS). I say that the
DOF of these two identical images - is exactly the same. I say that focal
length, aperure and focal distance determins the DOF.

IMO COF theories are somewhat subjective, because the point to where a point
looks like a disc, depends on the degree of enlargement. I think that the
smaller image, captured by a shorter focal length needs more enlargement,
thus less appearing less sharp.

What is right and wrong here?


Jens Bladt
mailto:[EMAIL PROTECTED]
http://hjem.get2net.dk/bladt






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