Contax Slr lens electrical connection failure

Hi there, just wondering if someone could give me a little advice. Have just bought a second hand Contax 159, which is really lovely, however when attaching my 28 mm and 50 mm Contax lens's, the aperture reading on the lens's does not correspond with the reading shown in the camera's viewfinder. This I have noticed is also the case when attaching the lens's to a Contax 167mt I have. That said I have recently attached the very same lens's to two Yashica FR's I have and the aperture lens setting does correspond to the aperture readings in the viewfinders of the Yashica's. So my assumption is that it must be the Contax SLR's that are possibly faulty? Just wondering if there is anyone who might be able to give me some advice reading this problem?

 

Cheers

Nigel Sinkins

Which exposure mode is set on each Contax? Do you get this problem in aperture priority or manual mode?

Hi Richard, thanks for your interest, The 50 mm lens is not an MM lens and the 28 mm lens is, in that its smalleset aperture is painted green.While the answer to your question is that both cameras are set to aperture priority, that said there is an aperture reading in the both camera viewfinders but as ive said it doesn't correspond to that set on the lens. For exampple with the Contax 159 the aperture is about on stop out while in its viewfinder the aperture reading at the bottom flickers and then goes out. Hope that helps. Cheers nigel

It is a long time ago since I used a Contax RTS. I do remember that this problem is well known. I believe it is a mechanical problem in the lens. The aperture is mechanically communicated to the camera body. When you look at the back of the lens and turn the aperture ring you can see a little "lever" moving. The position of the lever communicates the aperture setting. It also closes the aperture. You can simulate this with your finger by pushing the lever clockwise. I suspect that the lever is slightly out of spec. On some cameras it still works correctly but on others it communicates the next aperture. Being a mechanical problem implies that it can easily be solved. A problem is that Contax service has vanished a long time ago. Perhaps contacting a discussion group dedicated to Contax can be of more help.

Ferdi.

What aperture setting is set when you mount the lens? I'd try mounting them at both ends of the aperture scale and see what happens, it may even fix it!

I had a similar problem with my Contax RX, there was a 1/2-1 stop difference between what was set on the aperture ring and the aperture reading in the viewfinder. Perplexing as it was, my conclusion was that there was a slight misadjustment in the coupling mechanism on the camera body, and it only showed up with certain lenses, all of which worked fine on another body. I could never find the proper way to service the issue, so lived with it. I was concerned that it might throw the metering off, but apparently the film latitude compenated for it. Nevertheless, I did dial in compensation equal to about half of the difference.