p.5 #2 · Tuning Contax-Zeiss adapters to Canon lenses
Shirozina,
I just finished setting infinity on the Zeiss 28mm 2.8. This was much more dificult than the 50mm because the ring has Loctite or some other compound on it and it would not disengage. So I did a lot more disassembly than I intended.
But, everything is back togeather and working fine.
I think this is a very very important discovery for people that use adapters with lenses.
I should note, that when you make this adjustment, the setting may be specific the the adapter you use - perhaps at least the same manufacturer/thickness. If you put a thicker or thinner adapter on the lens after you make the adjustment, you may be right back where you started with no infinity.
Now I wonder how I can do this on my Zeiss 85mm 1.4?
Whoaaaa, just took off the focus rubber and there are 6 screws under there, similar to the way you adjust the 50mm 1.7. But it is late, I think I will leave that for tomorrow night.
p.5 #3 · Tuning Contax-Zeiss adapters to Canon lenses
Glad to help out - tell me how you get on with the 85mm. As for other ideas - I've just discovered that my 5D is backfocusing on the screen and AF - it seems to have drifted over time. I have discovered how to correct this - better keep a watch on the canon forum for the method when I make up the correct tool.
p.5 #4 · Tuning Contax-Zeiss adapters to Canon lenses
The Zeiss 85mm 1.4 turned out to be the easiest of all the lenses.
Remove the rubber focus grip, slightly loosen 6 screws underneath (I use 1/2 turn), rotate collar past infinity the desired distance, tighten screws, test, redo until satisfied.
p.5 #5 · Tuning Contax-Zeiss adapters to Canon lenses
I might be just being dumb - but I'll risk it.
At the moment I am researching adapters in anticipation of sharing my Zeiss lenses with a 5D or other Canon full frame digital.
Personally I fail to understand how some of my Zeiss lenses (which presumably worked perfectly on my film back cameras) suddenly need different flange to film distances to focus to infinity when put on another camera.
If there is some failure in the ability of the lens to focus to infinity - shouldn't that be a consistant problem regardless of camera? And if so then isn't it a calibration issue - something to be corrected on the lens and not on the adapter?
I can certainly understand the importance of machining tolerances, but mass production is based on parts being interchangable and ideally these adapters would all be interchangable across the line.
With all due respect - I appreciate the efforts that some people are going to in offering advice and solutions, but up to this point I definately feel that 'shirozina' has put the only information on the board that I can relate to.
p.5 #6 · Tuning Contax-Zeiss adapters to Canon lenses
beachcombersru,
I think it has been mentioned earlier in this thread. Or maybe another one on this forum. Anyway I can see you only have 1 post so that may explain why you may not know the situation. It seems the published specs for flange to film/sensor plane may not be entirley accurate.
Mosy of the commercially available adapters are made to the published specs. Pham is an exception to this but I ma not sure if he is still making them.
Jun 27, 2006 at 06:08 AM
jjlphoto Offline • • • • • [X]
p.5 #7 · Tuning Contax-Zeiss adapters to Canon lenses
Ditto on the above. After a year or reading hundreds of posts, and testings waaay too many lenses, the published flange to film spec provided by Canon seems to be the culprit. And it wouldn't be the first time specs on a published data was wrong. After hearing from engineers, it is more common that you'd think. Perhaps someone can gain access to a service or design manual, or take a plunge micrometer and measure it for themselves. But exactly what depth into the AA filter do you take the measurement if going in from the front? Makes it almost impossible to actually measure it.
Otherwise, real life data exists from members right here. 1.4mm seems to be the better adapter thickness based on tests by Don Clary indicating that the Canon EOS flange to film distance is really closer 44.1mm than 44mm.
Jun 27, 2006 at 07:58 AM
Andi Dietrich Offline [X]
p.5 #8 · Tuning Contax-Zeiss adapters to Canon lenses
I dont like to adjust my lenses myself, but I hope some people will do it and report back their experience.
p.5 #9 · Tuning Contax-Zeiss adapters to Canon lenses
You know John I mentioned it before and maybe it is coincedence but that difference is very close to the thickness of most film. I know it shouldn't matter because of where the filmplane reference is but I can't get over the coincidence.
Surely someone here has access to workshop manuals.
Jun 27, 2006 at 09:54 AM
jjlphoto Offline • • • • • [X]
p.5 #10 · Tuning Contax-Zeiss adapters to Canon lenses
Craig-
Most of the manufacturers place the focal plane just within the front surface of the film a little bit. (Just how far is up to them.) Even if Canon measured it only to the exact top of the surface (and not within), that would not be enough of an error that we are talking about. And if they measured it all the way back to the pressure plate, that would be a longer distance than we are talking about, then none of our problems would exist.
Now if Zeiss on the other hand measures their flange to film distance all the way back to the pressure plate, then we are onto something. Moving that measurement up to the front surface into the film like everybody else does, may actually give Contax lenses a flange to film distance of 45.4mm, so comparing that to Canon's 44mm, the diff is the 1.4 mm adapter that seems to work. But I really doubt that Zeiss would measure all the way back to the pressure plate. No one else does.
