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Zeiss Contax Distagon 28/2.8 Aperture

G

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Hello. I've just bought the S2 together with the 1,4/50 and the 2,8/28 lenses. I have a question about the apperture on the distagon 28. Is it not supposed to be hidden totaly when apperture 2,8 is choosen? For me it is visible, rather much. And also, there seems to be no difference in apperture size between f16 and f22. That is, there is equal ammounts of light through apperture 16 and 22. Is there anyone with any idea of what could be wrong?

Regards Kent
 
I'm not quite clear on what the problem is. Do you mean that when you have the aperture set at f2.8 the iris is still partially closed rather than wide open? And that when you close down from f16 to f22, the aperture stays at f16? If so, you've got a lens problem. As it happens, the only lens I've ever bought new that had a mechanical fault was the Zeiss 28mm f2.8. It froze at f2.8 and had to be sent back to the factory for repair under warranty. Only a shipping charge, I believe.
 
this is exactly what I meant. The equipment was used, and have a couple of years on its back. Therefore I have no warranty anymore. But at least I now know that this lens is supposed to behave like all other lenses I've seen. I guess I have to open it up and check out the aperture machanism. I will also check with Contax service to see what can be done in the matter. Thanks for the answer.
 
this is exactly what I meant. The equipment was used, and have a couple of years on its back. Therefore I have no warranty anymore. But at least I now know that this lens is supposed to behave like all other lenses I've seen. I guess I have to open it up and check out the aperture machanism. I will also check with Contax service to see what can be done in the matter. Thanks for the answer.
 
Kent,

>I will also check with Contax service to see what can be done in the matter.<

I will be interested in what you find out. This is exactly what I have with my D28.

Alex
 
It seems that no one have heard of this before. When I opened the lens I only took away the aperture ring. And there seems to be nothing wrong with the mechanism so far. I didn't remove the lensgroups to dismantle the aperture. Although I might do this since the cost for a repair almost matches the cost for a used lens anyway. The aperture blades seems to be clean, so I don't think thats the problem.

Alex, have your lens been this way all time, or have there been any incident causing this?
 
Kent,

>have your lens been this way all time, or have there been any incident causing this?<

It's always been this way, but it was not new when I bought it, and is out of warranty. The lens itself (MM model) is in very good condition otherwise, optically perfect, no barrel markings or wear of any kind. I noticed it more or less by accident because the exposure readings I was getting showed around 2/3 stop slower than my Planar 50, so I got all the lenses out and all the bodies out, and compared meter readings (fairly unscientifically). The Distagon 28 always showed slower. So I looked closely at the aperture blades, and at f2.8 they seemed to still be there are the edge of the lens, where the other lenses I have showed only glass.

I did contact Kyocera UK and they told me to send it to Contax in Germany, but I haven't done that, since what I hear from this list is that I'd be cheaper buying another. Exposures themselves seem to be fine, so I can live with that, and I don't think I have the courage to open a lens. It's just mildly annoying that a CZ lens should be 'out of tolerance' like this.

Alex
 
Do the aperture blades do the same thing with the lens mounted on the camera? You can operate it and see by holding the DOF preview. I seem to remember something like this, though my memory is very fogging. I may be off but it's worth a try. Jeff
 
Jeff,

>Do the aperture blades do the same thing with the lens mounted on the camera?<

When I put the lens on the camera, I can see the aperture blades when it's set to f2.8. When I press the DOF button, the blades move in and the aperture shrinks. Definitely not what I expected.

Alex
 
> > it's set to f2.8. When I press the DOF button, the blades move in and the aperture shrinks. Definitely not what I expected<<

Ya, that doesn't sound right. I remember I had a lens (can't remember which one) that the blades were visible until it went on the camera, then they retracted that tiny bit so evrything was as it should be. It's probably not much and just needs a service. I know a few repair places that have been good for me but they're in Canada, and I'm sure that's no help. Good luck, Jeff
 
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