Archived posting to the Leica Users Group, 1999/04/26
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Hallo Bernhard, You are correct on all your computations. Actual focal length of all lenses is not longer. If your 135 was marked 42 then its actual focal length would be 134.2. A 50 marked 9.2 would have an actual focal length of 49.2. As best I recall Erwin Puts posted that now Leica only makes one of the 50's in 3 focal lengths. My recollection is that the characteristics of each element is measured and a computer program 'decides' which elements to assemble to give resultant lens in one of the three focal lengths. One reason the exact focal length is significant is that even 0.1 mm difference will require a different focussing helicoid. I wonder what the various focal lengths of the Noctlux are. Dennis Bernhard Wingerter wrote: > > Hi! > I found this small numbers on each of my longer lenses. The 2/50 has also > 22, the 1/50 has 00, the 2.8/90 has 10, and the 3.4/135 has 62. Does this > mean the exact length's are 52.2, 50.0, 91.0 and 136.2 mm? Are all lenses > equal or longer than nominal? > > Bernhard > > -----Ursprüngliche Nachricht----- > Von: leica-users-admin@mejac.palo-alto.ca.us > [mailto:leica-users-admin@mejac.palo-alto.ca.us]Im Auftrag von Dennis > Painter > Gesendet am: Freitag, 23. April 1999 15:57 > An: leica-users@mejac.palo-alto.ca.us > Betreff: Re: [Leica] Summicron 2/50 No.:11825 chrom > > It means the focal length to the nearest tenth is 52.2 mm. Due to > manufacturing tolerances every lens' focal length can vary a bit from > the computed value. > ...