Archived posting to the Leica Users Group, 1999/06/13
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]The procedure you describe sets the focus at hyperfocal. If you don't have the DOF scale, just set focus directly at hyperfocal. Assuming a circle of confusion of .025mm, the following will give approximate hyperfocal distances in meters for 28mm, 35mm, and 50mm focal lengths. Just remember the numbers 30, 50, and 100. 28mm: Divide 30 by the f-number. 35mm: Divide 50 by the f-number. 50mm: Divide 100 by the f-number. For example, when using a 50mm focal length at f/11, set the focus at 100/11, or about 9m. Hope this helps. Maybe someone else knows a simpler way. Richard S. Date sent: Sun, 13 Jun 1999 12:03:39 -0700 To: leica-users@mejac.palo-alto.ca.us From: Michael Chmilar <chmilar@mminternet.com> Subject: [Leica] Tri-Elmar and Depth of Field marks Send reply to: leica-users@mejac.palo-alto.ca.us > I have recently been considering replacing my old 35mm Summaron f/3.5 > with the new Tri-Elmar. This, with my other lenses, would give me a good > range of focal lengths: 21, 28-35-50, 90. > > However, on closer inspection, I noticed that the Tri-Elmar does not have > the familiar Depth of Field markers around the focus indicator. This is > common amongst zoom lenses that use a ring for zooming. > > When I am shooting outdoors in sunlight, I often set my aperture, and > then crank the infinity mark over to the the DOF mark for that aperture. > Then I don't need to bother focusing, and I know I am getting the > maximum depth of field for the circumstances. > > Is there any simple way of retaining this capability when the lens is > missing the DOF marks? Is there a simple "compute in your head" > formula (I am only interested in where to position the infinity mark)? > > Mike > > -- > Michael Chmilar > chmilar@acm.org > > >