Archived posting to the Leica Users Group, 2001/12/10
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]i guess it took someone cleverer than me to point this out too! :-) - -rei > From: John Collier <jbcollier@powersurfr.com> > > When you fix the magnification of the final output relative to actual > subject size, then you are in effect removing focal length and focused > distance from the equation. The only variable left is aperture. The larger > aperture yields the smallest DOF. Not particularly useful info in the real > world mind you. The 75/1.4 and the 90/2 are more difficult to focus when you > are close and wide open which is what most people will want to know. > > John Collier > > > From: Rei Shinozuka <shino@ubspw.com> > > > > someone cleverer than i pointed out to me that for a GIVEN MAGNIFICATION, the > > noctilux is still DOF champ. in other words, you need to scale the distance > > by the focal length so that a cat or a face would be approximately the > > same size on the negative for each lens. > > > > using my favorite calculator: http://members.home.net/gillettm/DOF.html > > we get: > > > > f.l. f.stop. distance DOF > > 35 1.4 1.4m 13.1cm > > 50 1.0 2.0m 9.4cm > > 75 1.4 3.0m 13.1cm > > 90 2.0 3.6m 18.7cm > > > > the most surprising is that given these constraints, the 35 lux at 1.4m > > has the same DOF as the 75 lux at 3.0m! > > > >> From: "Steve LeHuray" <icommag@toad.net> > >> > >>> someone sed: > >>> > >>>> Plus, I love the > >>>> shallow depth of field that the 1.0 lets me use. > >>> > >>> i think someone posted a couple months ago a list of the DOF of various > >>> leica lenses -- i was suprised to learn that the noctilux wasn't really even > >>> terribly close to having the shallowest DOF (3rd or 4th if i recall) > >>> > >>> kyle > >>> -- > >> 3rd, with MORE dof than a 75 or 90. Why is that shocking? The longer the > >> focal length, the less depth of field. > >> > - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html