Archive 2006 · Tuning Contax-Zeiss adapters to Canon lenses
jjlphoto Offline • • • • • [X]
p.2 #1 · Tuning Contax-Zeiss adapters to Canon lenses
Craig and others have mentioned that its not unheard of for published data tables to be incorrect, or in this case, not clear. It is possible the 1.5 was a film EOS, and a sensor based EOS has proprietary flange to film distance as AA filter thickness is probably dirrerent on different models. Either way, it is entirely plausable that the entire adapter machining industry has been placing their fiath on the wrong number, as that's all they had access to. Empiricle evidence seems to indicate the 1.4 is better. Now if it is to be 1.395, 1.405, etc, that may never be determined with the reosuces available from members here. But the 1.4 sure seems to make a lot more people have success with adapters.
p.2 #2 · Tuning Contax-Zeiss adapters to Canon lenses
John, look at the white box with red top stripe picture. F-S is in the upper left of the red stripe. This is one of several versions of this Cinese made adapter. I prefer the version with a screw stop to prevent excessive rotation.
I didn't do any image corner inspections, but both the adapter before and after flange measurements were within .0005", as measured in about 15 points around the circumferenceof the adapter
May 25, 2006 at 01:19 PM
jjlphoto Offline • • • • • [X]
p.2 #3 · Tuning Contax-Zeiss adapters to Canon lenses
p.2 #4 · Tuning Contax-Zeiss adapters to Canon lenses
I don't see any mounting issues with the ground adapters. The only thing I had to do was to bend the clip a little bit so that it locks in place firmly. This has more to do with fotodiox than the act of grinding.
Don Calry wrote:
It sounds like shirozina's method is easier, if it works with your Zeiss lens (if you can get the rubber up, and if you know how much to adjust). I had no looseness issues with my 3 F-S adapters. Jameel did the mounting and testing, so he should comment about the tightness of the adjusted Fotodiox adapters.
p.2 #5 · Tuning Contax-Zeiss adapters to Canon lenses
It will also be interesting to shoot some film with contax/yashica bodies, scan and view 100% with photoshop and see how sharp the images are at infinity. I don't have any contax bodies. If someone in the seattle area has them, I'd be happy to try this.
p.2 #6 · Tuning Contax-Zeiss adapters to Canon lenses
Careful, Jameel, you may enjoy the Contax SLR so much that you revert to film.
The importance of film flatness to ultimate sharpness spurred Kyocera to produce a vacuum back for the RTS III. In conjunction with certain CZ lenses, correct calibration and careful technique, you can expect some serious results. Following is a vignette test of the P50/1.4:
Focus on building was between the 10m mark and infinity. Kodak Gold 100 was scanned at 4000dpi. 1x-scale crop shows the impressive wide-open performance in the corner:
Next shot had the same setup, with f/5.6 aperture. Various crops are 1x scale:
A distant stop sign is magnified to 8x scale, and processed to show detail approaching a single scanned pixel:
p.2 #7 · Tuning Contax-Zeiss adapters to Canon lenses
Good info here everyone.
Kit your comments regarding what John has said previously and what John has said are right on the mark. That was the first thing I noticed with those pictures was how the image quality just jumps out at you once the lens is sitting in the right postion.
I modified the Chinese F-S adapter that Don provided a link to. However I took metal of the EOS mounting face. This adapter measured 1.55mm initially and after turning we ended up with 1.45 +/-0.01mm. Not as flat as I would have liked. I haven't done any focus testing but I know it has not gone past infinty focus. I have a fealing it is a little shy of it but need to test it to be sure. The fit is not as tight as original but it is not loose enough to have freeplay.
I will machine another one and take it off the Contax side this time.
I spoke to the guy that makes the F-S adapter and they seem happy to leave them at 1.55mm. They say they test all right on their equipment.
I am investigating spinning some off here but my worry is that one of the established suppliers will get it right soon and make it not worthwile. Particularly if it is one of the cheaper Chinese manufacturers.
p.2 #8 · Tuning Contax-Zeiss adapters to Canon lenses
craig_oz_land wrote:
I spoke to the guy that makes the F-S adapter and they seem happy to leave them at 1.55mm. They say they test all right on their equipment.
If you should ever see him again, please bring up the subject again. I have three f-s adapters and although I am generally happy with them, I don't quite reach infinity with any of my 5 Leica lenses. Almost, but not quite. And they are quite consistent.
p.2 #9 · Tuning Contax-Zeiss adapters to Canon lenses
Hi Carsten, I did bring it up with him a couple of times but the penny didn't drop. He even sent me another adapter no charge. It measured the same as the other one.
Very good quality and consistent but if it is consistently the wrong thickness then what is the point.
Now I have to go and measure my Leica adapter after what you have just said
May 26, 2006 at 03:35 AM
Andi Dietrich Offline [X]
p.2 #10 · Tuning Contax-Zeiss adapters to Canon lenses
The f/s adapter can cause smearing. I had only one of these, so might just be mine, but I would recommend to test how they fit on the Canon side before you mill down hunderts of these.
shirozina, what lenses did you adjust with the procedure you mentioned? I have my doubts if this works for all Zeiss lenses.
p.2 #11 · Tuning Contax-Zeiss adapters to Canon lenses
bathman wrote:
The f/s adapter can cause smearing. I had only one of these, so might just be mine, but I would recommend to test how they fit on the Canon side before you mill down hunderts of these.
shirozina, what lenses did you adjust with the procedure you mentioned? I have my doubts if this works for all Zeiss lenses.
What is "smearing"? - I've adjusted my CZ50mm 1.7 and am about to do the same on my CZ28mm 2.8 although the procedure is different. All MF SLR lenses are internaly adjustable for infinity stop - it's how they set them up at the factory. Generaly they are quite easy to dismantle if you have the right tools ( microtools supply everything you need). The advantage if this method is the accuracy - if you shave a bit too much off your adaptor you have to throw it away.
p.2 #12 · Tuning Contax-Zeiss adapters to Canon lenses
Shirozina, very interesting
Do the CZ lenses have floating elements ?
I guess any with such elements will either be much harder to set up.
May 26, 2006 at 07:16 AM
jjlphoto Offline • • • • • [X]
p.2 #13 · Tuning Contax-Zeiss adapters to Canon lenses
Smearing is from an unparallel adapter. An uneven lens will have on corner look soft like the image was slightly smeared.
I would caution abot adjusting infinity stops, especially with floating element lenses. I had my lenses calibrated to factory spec by Zeiss themselves, and if even those do no allow infinity focus on a 1.5mm adapter, then I cannot blame the lens. There is noting I can do to it better than what the techs at Zeiss have already done. So that leaves only the adapter to be tuned.
p.2 #14 · Tuning Contax-Zeiss adapters to Canon lenses
was there any difference when shooting stopped down to say, f8? I can't remember the last time I shot a landscape wide open. (probalby never)
May 26, 2006 at 04:07 PM
jjlphoto Offline • • • • • [X]
p.2 #15 · Tuning Contax-Zeiss adapters to Canon lenses
If it ain't sharp wide open, it certainly won't be better at f8 than it would be if the lens was properly seated.
May 26, 2006 at 04:14 PM
Andi Dietrich Offline [X]
p.2 #16 · Tuning Contax-Zeiss adapters to Canon lenses
Smearing does not improve by stopping down to the same amount as other lens limits. If ever you have this problem you might still be able to use the adapter when it sits on the good place, but you will have smearing the moment you expect it least.
It will fall over you like Koto on Inspector Clouseau in the Pink Panther 3. No kidding!
p.2 #17 · Tuning Contax-Zeiss adapters to Canon lenses
Craig,
I'm sure I am not alone here in saying this.
We are using these zeiss lenses etc on our canon's because they give us an image quality the canon lenses can't match.
There are annoyances like hving to stop down but we can live with that..but worrying about not being able to get really good infinity focus every time is bad, especially when the joy and strength in the field of these lenses is that you should be able to turn the lens all the way and know you are at infinity!
If you found a way to make these adpaters, or even convert exisitng ones for proper infinity focus, you would be a very popular man..and we could then all go out and shoot without the worry of focus etc and just get on with creating.
I'd happily pay a bit for that privilege so keep up the good work!
p.2 #18 · Tuning Contax-Zeiss adapters to Canon lenses
Marc,
I am just heading off to some local repetition engineers right now for the (bad?) news.
My partner in crime who is a mechanical engineer tells me the big problem will be finding someone that can give repeatable accuracy on the two critical mounting surfaces.
Thanks to Don's and others testing efforts and the current dilemna I am motivated to come up with a solution.
I just found some specs on some Kodak 35mm film thicknesses.
KODAK T-MAX 100, T-MAX 400, and T-MAX P3200 films are 5 mil (.005 in)
KODAK PLUS-X and KODAK TRI-X Films are 3.6mil (.0036 in).
That is 0.127 and 0.91mm. I wonder if there is where the mysterious 0.1mm is hiding?
Could it be that Canon spec to the image sensor or film plane surface and Contax specify to the film backing plate?
Does anyone have access to service manuals and can confirm these figures?
May 26, 2006 at 06:39 PM
jjlphoto Offline • • • • • [X]
p.2 #19 · Tuning Contax-Zeiss adapters to Canon lenses
Supposedly, the font surface of the film would lie in the same place, and the thicker film would merely push the pressure plate further back as the front surface is pretty much dictated by the inner rails. Can't really sit closer that that unless it buckles forward in the center. Based on Dons tests, the empiricle data seems to indicate that 1.4mm is correct, so looking for any published data in any manuals is now moot.
p.2 #20 · Tuning Contax-Zeiss adapters to Canon lenses
I have been to the engineers this morning and should have an idea how much these things are going to cost to make next week.
Thanks John. Yes not thinking straight, haven't had my decaf yet . The inner rails of the film camera and so the front of the film plane should have been the same as the sensor plane ideally. So film thickness is probably irrelevant.
It would have been nice to have some confirmed specs that supported what others have found regarding the difference between the two mounts.
. The inner rails of the film camera and so the front of the film plane should have been the same as the sensor plane ideally. So film thickness is probably irrelevant.