Archived posting to the Leica Users Group, 1997/11/23
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]> Focal length has a lot to do with the accuracy of focusing with a > rangefinder. The longer the focal length, the less "width" the focusing > base has. Read Gunter Osterloh's book "Leica M" for a decent explanation. > The wider, the more accurate an M6 is. The longer (from 90+) the more > accurate an SLR is. > ========== The difference between an SLR and a rangefinders w.r.t focusing accuracy is that when a longer and/or faster lens is mounted on an SLR the focusing accuracy is increased, but on a rangefinder the focusing accuracy is the same regardless of which lens is mounted on the camera. If for example a Leica can focus to +/-1cm at 2 metres this will be much more than adequate for any wide angle lens, but will less than adequate for a 75mm lens at f1,4 where the depth of field is only 6mm. The depth of field figures come from the j'accuse Leica article at http://www.caliach.com/paulr/writing/jaccuseleica.html