True, but now try to explain *how* these factors work in a paragraph or two. That's what I've been trying to do.
chris On Thu, 27 Feb 2003, Bob Blakely wrote: > DOF has nothing to do with film or digital. The only things that affect DOF > are: > > 1. Focal length > 2. Aperture. > 3. Distance to focus (usually subject). > 4. What tolerance you accept as "in focus". > > Regards, > Bob... > --------------------------------------------------- > "Going to war without France is like going deer hunting without an > accordion" > - former Deputy Undersecretary of Defense Jed Babbin > > From: "Chris Brogden" <[EMAIL PROTECTED]> > > > > On Thu, 27 Feb 2003, Maciej Marchlewski wrote: > > > > > Dnia 26-02-2003 o godz. 23:15 Chris Brogden napisal: > > > > > > > The myth about digital offering more DOF is partly true, > > > though. To get a > > > > DSLR lens that magnifies things as much as a 50mm lens for a > > > 35mm film > > > > camera does, you'll need to go with a DSLR lens with a focal > > > length of > > > > roughly 35mm (assuming a 1.5x conversion factor). When a > > > subject looks > > > > the same size through a 35mm lens and a 50mm lens, the shot > > > taken with the > > > > 35mm lens will have more DOF than that taken with the 50mm > > > lens. > > > > > > AFAIK if your subject is of the same size the DOF is exactly the same > > > regardles of focal length used. > > > > Not true. Using a film camera, take a picture of a person with a > > telephoto lens so that all you can see is their head and shoulders. Then > > put a wide angle lens on, and walk closer to the subject until you can see > > just their head and shoulders. Now your subject is the same size as it > > was with the telephoto lens, but you have much more DOF. > > > > If you stand in one spot and use different focal lengths, the DOF and > > perspective will remain the same (you're basically just cropping), but the > > subject size will change. If you change your position so that the > > subject size remains constant with different focal lengths, the DOF and > > perspective will change. > > > > > In DSLR we have a bit different case - the subject is not projected on > > > media as the same size - it is smaller in APS DSLR and than magnified > > > so it seems as it uses the same part of the frame as in regular SLR. > > > So here we have a case od the same subject distance giving as the same > > > frame with different focal lengths. And this results in greater DOF on > > > APS DSLR. > > > > I'm a bit confused by your wording here, but I think I agree. :) > > > > chris > > > > > >
