Archived posting to the Leica Users Group, 2003/07/30
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]>A common mistaken notion. Focal length does determine focusing >accuracy with rangefinders. As the focal length increases, accuracy >drops. And at about 75 mm, the rangefinder becomes about as accurate >as focusing with an SLR. The wider the focal length, the more >accurate a rangefinder is compared to an SLR. Well, from a strictly anal (this *is* the LUG) perspective, you're wrong. The focusing error on an M7 @ 1 meter will always be +/- 1 cm (to just pull a number out of thin air). For a 35mm f/2 lens, that's covered by DOF amply. For a 50mm f/2 lens, that's covered by DOF. For a 75mm f/1.4 lens, we're starting to get to the point where either bounds of the +/- 1cm will be visible. So the focusing *accuracy* of a rangefinder is constant, it's just that that accuracy will be visible with certain lens combinations. Karen Nakamura - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html