No, I have no objections to a resurrected, four year-old thread filled with back and forth and back and forth and lots of posturing and stuff....
Yes, being in
this thread certainly was my mistake. Went wrong somewhere, I still can't figure out how I got here.

Prowling around without enough attention obviously, got sidetracked. Sorry about that part.
I intended to be in this thread:
http://www.thephotoforum.com/forum/...th-field-lenses-relationship.html#post3215301
where yesterday you had posted there about DOF and my "it's all crop" nonsense, and then thought better I guess, at least apparently deleted it quickly, or someone did. But I don't mind discussing it with you.
There you pointed out the obvious DOF difference in 35mm and roll film and sheet film, and digital compact, DX and FX, regarding depth of field. Those factors are "all crop", so we already agree.
You seem to credit DOF to the film itself, but I realize you cannot mean it that way. I feel sure you know and care.
But sure, I will word it that way if you wish, yes, of course it is all crop.
Crop is the only difference in any of those cameras, how much their sensor crops the lens view. It could be worded how well the lens covers the film size, but of course, that is specifically about the crop size.
They of course do also necessarily use different lenses, but which needed magnification is ONLY because of the crop size, so it will see a normal view, so yes, of course it is all about crop. And of course, their varying sizes also have to be enlarged differently later (more magnification), so again, it is all crop.
Other than aperture fstop, what does affect DOF is magnification, which could be lens focal length or focus distance, but all specifics come about because of crop size. How hard is that?
You had said: "If you WANT TO MAKE pictures that have VERY LIMITED depth of field, what people have done for well over 100 years, is to use a BIG piece of film."
That 8x10 is of course just a bigger crop size, pure and simple.

Of course, the film does not actually do anything about DOF, but the crop size demands use of the lens that does cause it.
So, how is this statement wrong? If you want a drastic difference in DOF (for an assumed similar view of a subject), find a camera with a drastically different crop size. (I just quoted your agreement)
If crop size is not the FIRST STEP, then what would be the first step?
