Contax 50mm: Aperture blades problem

[Nikos]

A couple of months ago I bought a 50mm Planar on eBay which looked in great shape.
It really is, except that when stopping down from f11 to f16, the aperture ring was more stiff and you have to exert greater pressure.
"Who cares?", I thought, as I rarely use f16.

The real problem is that when used on my 5D II with an adapter, the problem appears as early as f4 --> f5.6.
Sometimes, the aperture ring turns, but the aperture remains the same. I have noticed that
unscrewing the lens a bit, makes the aperture blades move to the right position.
But this is very irritating and not a solution when you are in a hurry.
In general, when the lens is not mounted, the aperture works more or less fine.
Perhaps the problem is amplified by the adapter, but it happens with 2 adapters by different manufacturers.

Is there a way to fix this?
It is the MM version, SN 809XXXX

Thank you.

[cambug]

One probable cause of this problem is with the lens aperture opening lever. For some Contax lenses and Canon FF bodies, this lever ( its only function is for Contax camera bodies, that irrespective of chosen aperture setting, it opens up the aperture fully for focusing, it retracts to let the aperture to stop down just before exposure) could touch the matte box (above the AF electrical connectors and below the mirror ) and get stuck. In this case, the aperture would be kept at either fully open or some other settings. You can check if there is any scratch mark inside the lens mount, if scratches can be found, this is the cause. The lever can be filed down a bit and it would not get stuck, the aperture movement would be free again. Good luck and have fun checking...

[Orio]

Nikos, I had the same problem with all the copies that I tried (three).
It is a problem that comes out of the interaction of three elements: the lens, the adapter, and the camera.
For instance, the same combination lens-adapter that does not work on my FF cameras, did work with the 50D.
So one actor is the camera and specifically what is different between the 5D (I and II) and the 50D.
Another actor must be the adapter, because there is people who reported to have used the lens successfully with their adapters. My adapters don't work, but I can't tell about other adapters.

I finally solved the problem by... buying the ZS version of the lens

[AhamB]

[Nikos]

[Nikos]

[Morfeus]

[Himself]

I had the same problem with my 50/14 MM that I had from Andy.
I had to write him back and he told me to switch the adapters. I had 2 adapters, one chipped the other one not.
It worked with the non chipped adapter.

[Nikos]

I did not feel like filing my lens.
I think I have found a very simple and non-destructive solution.

The goal anyway was to prevent the lever from traveling.
So, I just blocked its way with a piece of plastic that I cut from my pills packaging:



Seems to work fine

[AhamB]

[Scheimpflug]

[Nikos]

[Keysersoze27]

Had the same problem with 5DII and 3 of my Contax lenses (not my 1.4/50 MM one).

I just used a electric nail filer using a metalic head (my girlfriend's staff ). It only took >2 minutes to file just >0.5mm ....nothing more!!!. Then used an acrylic black paint to cover the edge. Lenses work perfectly on my RTS after this tiny operation so no problem in this department;)

Φιλε Νικο,

Check the inside of your 5dII ... you should have a elliptic scratch in the inside plastic part of the camera's body where the aperture level is still touching

[Scheimpflug]

[Nikos]

[Keysersoze27]

[Orio]

Nikos method works! Thanks much for the tip!
If I knew it before, I would have saved 550 Euros

[rhapflan]

hi morfeus. you said when you filed down your contax 50mm, you "Closed the opening of the lever with some plastiline, to avoid metal dust falling inside the lens." i'm not familiar with the term plastiline. do you know if there's another trm for that. and did you cover the channel in which the lever slides? any details you can offer would be appreicated.

thanks

[Orio]

[Nikos]