Archived posting to the Leica Users Group, 2001/11/29
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Seth I have just unscrewed the lens head on my DR Summicron an do indeed see the inscription you mention. My lens number 1833907 is marked 51.9 N , hope this is info is of some help. Best Regards Eric (Liverpool U.K.) > Dan: > > I wish I knew. I've not seen that before. I will make a guess but remember it > is pure guess: the 39 was on the lens at birth, meaning 53.9 (although I > don't recall ever seeing a number that high). Then the lens was rebuilt, > perhaps in order to be a dual range, and became 51.9 N(ew)? Just conjecture. > Can't figure out what else it might be. The fact that the second set of > numbers is of a differrent size makes me wary that it may not have been the > factory that did it. > > I also wonder if you have noticed any problems with focus? If the lens head > is misfitted, your photographs should be somewhat out-of-focus. > > John Collier is correct though: you need to have the lens examined by a > really competent repair facility that knows what it is doing to regularize > whatever is going on with your lens. Incidentally, what is the serial number? > > There were two changes in the DR/Rigid Summicrons: the coating was changed on > the later lenses and improved to enhance contrast. And the focussing mount > was also changed. The first series has the grooves that are cut into the > focussing ring on the outer raised surfaces of the ring; with the later > lenses, the grooves are cut into the indented scallops of the ring. I'm not > sure that the changes took place simultaneously not what were the serial > numbers at which changes occurred. > There has always been some conjecture that the optical formula of the lenases > was also changed. I have correspondence with both Wetzlar and Solms that > confirms that the actual optical design - apart from the coating modification > - didn't change throughout the production run, 1956-1970. > > Because your result with the numbers and this response might be interesting > to LUG readers, this technologically challenged LUGGER is going to try to > forward both. > > Best, Seth LaK 9 > -- > To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html