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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 |
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