Re: Contax 645 to Canon EF Adapter Initial Impression
Using this adapter on A7/R: not very exciting.
I tried using this adapter on A7/r with Metabones III, and I\'m afraid to say that it\'s quite limited. There is no AF, no aperture control, and no lens information in Exif. You have to use this adapter with lens wide open, and even that is iffy.
The first lens I tried was 45/2.8. As soon as the adapter and lens were mounted, the lens aperture blades closed to the smallest. This is not a good sign. In A mode I was able to control aperture from camera, but that didn\'t do any good because, with aperture closed, metering was way off. I ended up getting almost pure white pictures. Not sure if there is any Exif in these pictures -- I deleted them immediately in camera.
Then I mounted 120/4 macro. There was no aperture control, and the lens remained wide open. Metering was good and I was able to use it normally in A mode. No Exif.
Then I mouned other lenses -- 140, 80 and 35. All worked like 120mm. You have to use the lens wide open. There is no aperture control, no AF, and no Exif.
Then I mounted 45/2.8 to Canon to open its aperture, before mounting it again back on A7r. To my surprise, it worked like the others. There seemed to be some memory with the adapter.
I then tried to exchange lenses after turning off the camera and pulling out the battery, and it didn\'t seem to help. At some point, 35mm closed its aperture when mounted, and it happened to 140mm as well.
Observations:
1. When the lens closes its aperture when mounted, it cannot be used, even though there is AF control from camera.
2. 120/4 macro is definitely usable with lens wide open, without AF or Exif.
3. Other lenses are also usable wide open, but somehow some lenses may still close aperture, in which case you can mount the lens to a Canon body and the aperture reopens. Not sure what\'s causing the lens aperture to close. Mounting 120/4 seems to give the next mounted lens a better chance to work w/o closing its aperture.
4. The eletronic circuits do not seem to communicate well between this adapter with Metabones EF-NEX III. Maybe the vendor can tweak the firmware in the future. But as of now, if you are thinking of using this adapter on A7/r, you will be disappointed. It is designed for the Canon body, not A7/r. It still has great performance when used on a Canon body.
Apr 19, 2014 at 12:44 PM
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