Archived posting to the Leica Users Group, 1996/07/20
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Eric Welch wrote: > > At 08:49 AM 7/20/96 -0400, you wrote: > >What's different about the M3? Longer baseline? Better Viewfinder? This is > the first I've heard that it may have more accurate focusing? > > It doesn't. Accuracy of the rangefinder is based on the baseline of the > viewfinder, and as far as I know, they are all the same in the M line. The > CL and CLE are shorter, which is why they don't work as well with the Noctilux. > > The M3 does have a higher magnification in the viewfinder, because it > doesn't have to accomodate lenses wider than 35 without some optical trick. > But I doubt it makes a difference in focusing accuracy. The reason why the M3 focus more accurate is because the effective base is longer. The physical base line is for all M-models the same 69.25 mm. This figure has to be multiplied with the magnification off the rangefinder. For the M3 0.9, for the M6 0.72. This muliplication gives the effective baseline which determines the theoretical accuracy off the rangefinder. That's why the srcew leicas from model 3 have a magnification of 1.5 wich gives with a physical baseline of 38 mm an effective baseline of 57mm. So in theory the screw leicas are mor accurate than the M6 which has an effective baseline of 49.9mm. Off course also the mechanical accuracy of the mechanism is important and also improved over the years. The CL has an effective baseline of 31.5 and is therefore not accurate with long and/or fast lenses at open apertures.I often use a slim tele-elmarit 90 on my CL but it definitely does not focus well at 2.8. Greetings, Michiel.