Arjay
Time Traveller
I recently bought a CV Ultron 28mm/f2.0 M bayonet lens off of the bay. Cosmetically, the lens looks like new, but when I put it on my Hexar RF, it behaves very strangely:
I was shooting the obligatory roll of test shots only to find that when looking through my finder, the rangefinder can go beyond infinity! I tried to focus on an object some 400 - 500m (~ 1/4 mile) away, expecting this distance to be far enough as to pass as infinity. With this lens on my camera, the viewfinder has features coinciding before the lens is at its infinity stop - the difference is ~2 to 3 degrees.
My camera works correctly and consistently with both my Hexanon 35mm and 50mm lenses, so I think the Ultron is at fault.
So here's my question: Does anyone know whether it is possible to adjust the lenses RF coupling ring for correct rangefinder synchronization?
It appears that with M bayonet lens designs, there are some gears between the distance setting ring and the internal lens barrel that moves the optical system. The ring's angle of revolution as well as the sync ring's travel in relation to the lenses optical axis must be standardized, but obviously, the the optical system's travel is dependent on focal length (and probably other design-related parameters). This is why I am thinking that this type of design must offer some mechanism for rangefinder sync alignment. And no, aligning the camera's RF cam isn't the solution because that would throw all other lenses out of sync.
So, can anybody confirm that such an adjustment is possible?
I was shooting the obligatory roll of test shots only to find that when looking through my finder, the rangefinder can go beyond infinity! I tried to focus on an object some 400 - 500m (~ 1/4 mile) away, expecting this distance to be far enough as to pass as infinity. With this lens on my camera, the viewfinder has features coinciding before the lens is at its infinity stop - the difference is ~2 to 3 degrees.
My camera works correctly and consistently with both my Hexanon 35mm and 50mm lenses, so I think the Ultron is at fault.
So here's my question: Does anyone know whether it is possible to adjust the lenses RF coupling ring for correct rangefinder synchronization?
It appears that with M bayonet lens designs, there are some gears between the distance setting ring and the internal lens barrel that moves the optical system. The ring's angle of revolution as well as the sync ring's travel in relation to the lenses optical axis must be standardized, but obviously, the the optical system's travel is dependent on focal length (and probably other design-related parameters). This is why I am thinking that this type of design must offer some mechanism for rangefinder sync alignment. And no, aligning the camera's RF cam isn't the solution because that would throw all other lenses out of sync.
So, can anybody confirm that such an adjustment is possible?
Krosya
Konicaze
I dont know if it is possible to adjust the lens, but what about the results? Do photos come out in focus or not? In reality - who cares what distance scale say if it focuses correctly. Now, if it doesnt focus correct - than you may have a problem that someone like DAG may be able to address.
Arjay
Time Traveller
Thanks for your quick reply! Unfortunately, I don't know yet if the lens is actually focussing correctly, as I'm still waiting for the test film to come back from processing.
Also, DAG probably isn't a very useful contact for me as I'm living very far from the US - in Germany.
Does anybody know of CV lens service manuals? I'm aware that if I'd open the lens on my own, I'd probably riun it since most probably, I don't have the right tools let alone the right background knowledge. But still I'd like to know if such an adjustment is feasible, or if I should just return the lens to the vendor on the bay (not sure if that's such a good idea as I got a very good price).
TWoK
Well-known
The markings on the lens of course matter for hyperfocal shooting.
Krosya
Konicaze
Well, sure, but most people dont do that much and for the stopped down wide angle lens it's not really all that precise anyway, right?
beanous
Member
Hi, has anyone ever dealt with this issue again? My 28/2 Ultron also has a misaligned focus -- thought someone might have managed to open/align the lens themselves in the meantime?