As a suggestion when you post the lens that works you include the serial number with the last 2 or 3 digits XXX'd out. I know Leica changes lens design's without notifying users, ditto Zeiss. You also can post the list on Leica page of www.photo.net to get others feed back.
I've just joined this forum because of the excellent information and reasoned discussion available. Good stuff.
I'm particularly interested in the CZ compatibility issue, as one of the reasons that I recently purchased a 5D was the presumption that it would work with my CZ lens collection. At the moment I have a cheap Chinese throw-away adapter bought from Eb@y, while I decide whether I really should buy a more expensive adapter - provided it's a good fit and the stops are in the right place it shouldn't be a problem.
I have the 24-105L and the 50mm f1.8 EOS lenses, which I will use as benchmarks to assess any increase (or decrease) in performance of CZ lenses
I have so far tried the CZ f2.8 25 AE, 35 f2.8 MM. 28 f2.8 AE and 60 f2.8 Macro Planar 1:1 AE. I have several more to try but have not had time to yet. First impressions are that these all mount OK, although the only one that I have tried at infinity was the 25, which is then a little soft across the image (including centre), so I think that I may have an issue, although I shall repeat the infinity test on thsi an other lenses.
I like to try to think these things through from first principles, so correct me if you think I'm wrong ! I understand that if you use an extension tube, you lose infinity focus, I guess because the infinity focus plane is now in front of the sensor/film. Hence it follows that if the adapter is too thick, then you will lose the ability to infinity focus (if your lens has an accurate stop at infinity, as the CZ's all seem to do). Similarly, if the Canon body flange to sensor plane distance is too long, then the same effect will show up.
If the adapter is too thin, then the infinity stop will be past infinity. Hence infinity focus should still be possible, but you have to retreat from infinity somewhat.
This doesn't seem to square with those posters who are seeing infinity focus problems when their adapter is too thin i.e. 1.4mm rather than the correct 1.5mm. I'm going to try to get hold of a micrometer to check in the thickness of my adapter........
Any thoughts? It would be interesting to know whether, if I do have a problem, I shall need to skim, shim or replace my adapter! Or whether there is another explanation completely?
frasergjb wrote:
Any thoughts? It would be interesting to know whether, if I do have a problem, I shall need to skim, shim or replace my adapter! Or whether there is another explanation completely?
Rgds
Fraser
Welcome, Fraser and thankyou for your feedback! Here u'll find the CZ-to-5D list (includes different adapter types). Please, post your tests&findings there, so that I can update the list. Thankyou again!
frasergjb wrote:
This doesn't seem to square with those posters who are seeing infinity focus problems when their adapter is too thin i.e. 1.4mm rather than the correct 1.5mm. I'm going to try to get hold of a micrometer to check in the thickness of my adapter........
Rgds
Fraser
Welcome to the forum, Fraser.
I'm not sure if those were actual measurements or manufacturing specifications. If the 1.4mm were manufacturing spec, then it's possible that the adapter was actually made thicker than that and not allow infinity focus. Also, even if the adapter is 1.4mm thick in some places, if other sections of the adapter are 1.6mm thick, then it may not give you inifity focus. I think that's why that poster wrote that manufacturing precision is extremely important.
I'm not sure if those were actual measurements or manufacturing specifications. If the 1.4mm were manufacturing spec, then it's possible that the adapter was actually made thicker than that and not allow infinity focus.
Peter
Thanks for the welcome Peter.
I got the idea that +1.5mm was correct from this table:
I would love to hear if the 28/2.8 and 50/1.7 work with the 5D, does anyone have these combos? I'm using Son's adapter, I'm not sure how it compares in thickness to the rest of them.
frasergjb wrote:
I'm not sure if those were actual measurements or manufacturing specifications. If the 1.4mm were manufacturing spec, then it's possible that the adapter was actually made thicker than that and not allow infinity focus.
I got the idea that +1.5mm was correct from this table:
The Leica R register is +3mm, which of course means they are further from the 5D mirror.
I've got no idea whether the data is correct, or what the critical tolerances are.
It is not just as simple as just making the thickness right. Every adapter will introduce two more surface alignments, and a little inaccuracy in the alignments will introduce bigger error than the thickness itself can contribute.
Daniel Buck wrote:
I would love to hear if the 28/2.8 and 50/1.7 work with the 5D, does anyone have these combos? I'm using Son's adapter, I'm not sure how it compares in thickness to the rest of them.
Gary reported above that those lenses work with the 5D.
Son's 2nd generation CZ-EOS adapters ARE Fotodiox adapters (the black ones). I don't know about his 3rd generation adapters, and I don't know the specs on those adapters.
PSquared63 wrote:
Graham, the flat, broad piece on the adapter that abuts the lens as well as the camera mount is where you measure the thickness.
Well, it just makes no sense. That plate is only ~1.2mm thick so my 50mm should focus PAST infinity, but it can't get past 10m. (My 135mm gets as far as ~200m but still not infinity).
