Archived posting to the Leica Users Group, 2001/02/07
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Or.. I could be a complete and total idiot.. don't leave out the idiot factor! ;) - -Mark On Wed, 7 Feb 2001, John Collier wrote: Obviously this thread has gone on so long that the hypothetical illustrations are now being confused with the main point. Time for a segue....Martin? Heck, I would settle for a non-sequitur at this point....Kyle? John Collier :-) > From: Mark Cohen <markc@binaryfaith.com> > > > > Um.. isn't a 90mm on a 4x5 a wide angle lense whereas a 90mm on a 35 is a > telephoto... > > Not to mention that a 4x5 camera takes into account the COC and the image > area on a 35mm doesn't. > > > You really can't compare 4x5 to 35mm in _any_ way :) > > -Mark > > > > On Wed, 7 Feb 2001, John Collier wrote: > > Not at the same print size. The image size on the negative is the same, as I > already pointed out, but the final image size is different when the print > size is the same. Which is why the DOF tables vary according to film format > as well. > > For example: > > A 4x5 camera and a 35mm camera, both with 90mm lenses, take a picture of a > subject at the same subject distance. Now make a 4x5 print of both negatives > using as much of the negative as possible. This is a contact print for the > 4x5 negative and a, approximately, 4x enlargement of the 35mm negative. The > resulting image size is "smaller" on the 4x5 contact print regardless of the > fact that image size is exactly the same on the negative. A smaller image > size will result, if the same relative aperture is used, in greater > perceived ?thank you, Martin? DOF. > > >> From: "Austin Franklin" <austin@darkroom.com> >> >>>> I disagree. If you take the same lense, and use it on ANY size >>> film, at the same distance, you will get the same DOF. >Optics >>> doesn't know what the film size is, and adjust it self accordingly. >>> 3' IS 3', no matter what the film size is. >>> >>> That is like saying that a 24mm lens @f8 on 35mm has the same depth of >>> field as a 500mm lens @f8 on 35mm if you enlarge the 24mm image >>> sufficiently. >> >> No it is not what I said. I said, quite clearly, that the same 50mm lense >> at 3' gives the same DOF on both 35mm and 4x5 film. >> > - ----------------------------------------------------------------- Mark Cohen (BALUG LHSA AFA) 226 San Carlos Street #1 "MIS people have sick, twisted San Francisco, CA 94110 little minds" -Linus Torvalds (home) (415) 970-9421 (pager) (888) 702-9872 (cell) (415) 290-7201 (work) (415) 633-1179 page-mark@binaryfaith.com *** The box said "Install NT 4.0 or better", so I installed UNIX *** - ----------------------------------------------------------------- - -----BEGIN GEEK CODE BLOCK----- Version: 3.1 GCS/FA/MU d? s+:+ a- C++++ ULBS++++$ P- L+++ E--- W-(+++) N++ o? K? w--- O? M-- V-- PS+++ PE Y++ PGP++ t+ 5++ X R+ !tv b+++ DI+++ D+ G++ e++ h++ r% y+ z** - ------END GEEK CODE BLOCK------