Lense, f-stop, focal point... DOF....

"Jonathan Wilson" wrote in message
...
Ok, so with a given focal point... lense mm, and F-stop, you can just
about work out a DOF "in focus...."

The main difference, from experience, is that a PAS has a large DOF
and a "common" dSLR as a smaller DOF[My personal experience] (and if I
used it 35mm has less dof, and medium format even less and Large
Format a DOF so small its bordering on the bizzare!)

So knowing what I know about the basic theory about the above....

Is it posible to have a lense that "gathers" enough light to equate to
say F1.8, but reduces that to a focal plane and film size that equates
to an f11?

I know the maths is off based on numbers... but what I am thinking of
is a large DOF but a low f-number....

You can cheat in some cases, if the stuff you want to be in focus is roughly
in the same plane in space. Look up Scheimpflug in Google. With a Canon
dSLR, you can buy a TSE lens that allows you to do that. They're slow
(f/3.5) lenses, though. And not cheap.

David J. Littleboy
Tokyo, Japan