Archived posting to the Leica Users Group, 1998/02/06
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]At 10:47 PM 2/6/98 -0800, you wrote: >> From: BenTroGa@aol.com >> To: leica-users@mejac.palo-alto.ca.us >> Subject: Re: [Leica] Macro Question >> Date: Thursday, February 05, 1998 6:40 AM >> >> Frank: For simplicity: Same size image + same aperture = same depth of >field. >> (No matter whether it is a 15mm or 1000mm focal length, if the aperture >is the >> same, and the image size is the same, the depth of field is identical. >Period. > >The depth of field calculator at: http://ue3.ee.nus.sg/DOF.html >contradicts the above statements. For 35mm film a 50mm f1.4 lens focused at >100 feet gives a depth of field of 138 feet, a 100mm f1.4 lens focused at >200 feet gives a depth of field of 110 feet. > >Any comments? It's a well established physical fact, written about in nearly all photography books, including Ansel Adams' books. The same image size in the viewfinder, with different lenses, still gives the same DOF. All I can conclude is that the Java Script (that in itself is suspect) calculation program has a bug. I would never trust the results of a program, without rigorously testing that it indeed is doing what it is supposed to do. IMHO, Jim