Archived posting to the Leica Users Group, 2001/12/10
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]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