The Mystery Deepens
The Mystery Deepens
See my message quoted below regarding Sonnar C 50mm optimization. I called the Carl Zeiss U.S. Marketing and Sales Director today to see about getting my new Sonnar optimized for f1.5 after receiving the message from Carl Zeiss in Germany. He tells me that from March 2007 on, the Sonnar 50mm
has been optimized for
f1.5, which is consistent with what I've read here and on other boards, but which is inconsistent with the message from Carl Zeiss Germany. At this point, more sources than not have the lens optimized at f1.5. So I guess that will be my working assumption.
The U.S. rep did, however, say that the f1.5 calibration is done on a bench for 27.6mm from the sensor/film plane, and that the M8, M8.2 and M9 generally do not conform to that spec, although the film Ms do. He said that Zeiss can calibrate the lens for M9s at no service charge within the warranty period, but that once that fix is done, the lens may not work well wide open with a film M. I guess that stands to reason, if the film plane of film Ms and the sensor plane of digital Ms are not the same distance from the lens. Sheesh!
I think I'm going to try the thing out at f1.5 with my M9 and M3, see if there is a problem that my poor eyes can see, then decide what to do. With luck, I will not be able to discern a problem, in which case, it doesn't exist!
Interesting news below. Having read about the focus shift issues of the C Sonnar 50mm, which haven't troubled me with mine so far in the few weeks since I bought the lens new, I queried Zeiss about the optimization aperture. I was under the impression from what I had read here and elsewhere that the newer C Sonnars were optimized for no focus shift at f1.5. That is apparently wrong. Here is what I got back this a.m:
"Thank you for your inquiry to Carl Zeiss.
Out of factory all the C- Sonnar lenses are optimized for best compromise
of the unavoidable focusshift at f 2,8. This seems the best adjustment for
most of the applications. If you like to have the switch to the widest open
optimization you have to send the lens to your dealer or our distribution
partner in the land of purchase and they will forward the lens to the
service in Oberkochen. Within the warranty time this service is for free.
Hoping to be of service to you we kindly ask you to contact us again should
you need further assistance.
Sincerely,
Andreas Bogenschuetz"