Archived posting to the Leica Users Group, 2001/01/06
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search](This is about optimizing telephoto lens/rangefinder combo for focusing at short distances) >Chris. I did it myself - took a lot of time and involved groundglass, >tripods, lots of film and strangely shaped screwdrivers (to get at the screws >in the M3's focussing system). I would recommend that you find a good Leica >technician and have him do it. Decide which body is the dedicated 75/1,4 and >have it matched to the lens. I have seen these lenses work perfectly at all >distances and I have seen them be off by a foot at close range. It does sound >like a bit of a hassle, but once you get it rite, it is one of the truly >awesome lenses ever made! I would love to find out if it is possible to make >a mask for the 75/1,4 that would work on a M3 - even if I had to sacrifice >the 90 or even the etched 50 mm frame - it would be a great combination. One >day I will take a M3 viewfinder apart and see what can be done! >Tom A Thanks for the reply, Tom. I just read an article about how to determine how to focus for IR film and I think I will use the method proposed there to check if my camera body and lens combo focuses correctly. The method proposed (adapted to close range focusing) was: - - set lens to shortest-but-one distance marked on the barrel - - fix a piece of paper with a vertical line on a wall - - place camera on tripod - - adjust distance camera to wall so that vertical line is shown unbroken in finder - - expose one frame - - turn lens barrel (the one with distance scale) 2mm clockwise and expose - - turn another 2mm and expose (repeat a few times) - - go back to situation with unbroken line in finder and expose - - repeat procedure above but turn barrel anti-clockwise You may want to put the sticky portion of a post-it marker on the lens barrel with different coloured markings for the 2mm steps, and you may want to put post-it markers on the wall indicating how much you are off the distance marking which had been indicated to be correct. This helps greatly when reviewing the prints. I will try this out with my skinny Tel-elmarit - a truly sharp lens, but not always with sharpness where I want it Chris - -- Christer Almqvist D-20255 Hamburg, Germany and/or F-50590 Regnéville-sur-Mer, France