Contax RX body-lens connection problem

Discussion in 'Classic Manual Cameras' started by george_daneliya, Jan 30, 2009.

  1. Haven't found special thread for Contaxes, thus I'm here.
    Two Contax RXs I owned had the same problem with body-lens connection (?). The issue was that with some of lens oftenly the camera wouldn't react if to switch the lens from more closed diafragm meaning to more open (16 > 11, 8 > 5.6, etc.) :( The problem never happens with yashica lens, only with Germany and Japan made CZ...
    I thought it was common for the first camera only, until very recently I've acquired the second one (hadn't chance to test it when buying - had no lens with me at the moment; and cannot return it also - I bought it in Tokyo, while now I'm in Moscow).
    Maybe someone already faced such problem? If so, what could be possible solutions? (Please, don't advise to get it to repairmen, CLA, or throug away - I need more concrete info).
    Thanks a lot in advance!
  2. Forgot to mention - the problem affects exposure.
  3. George, clarify what you mean. You open up from, say, f/16 to f/11, and what do you mean the camera doesn't react? It doesn't read the change in aperture and adjust the change in metering accordingly?
    I don't have an RX, I have 6 or 7 other Contax SLRs. Never seen this problem. I'd check the lenses and see whether the lugs on the back are moving smoothly when you change apertures.
  4. August, thanks for answering!
    Exactly, the camera (both cameras) doesn't read the change in aperture and adjust the metering accordingly. While mechanically aperture works as it should. For example, if to open aperture from 16 to 11, the camera would meter as for 16, but the aperture would work/close as 11.
    As I said, I have the problem with 2 RXs with the same lenses - 1,7/50 (made in Japan), 3,5/200 (Germany). All lenses are in excellent condition mechanically and optically.
    I also have another problem with 2,8/135 (Japan), which is in LN- condition. Both cameras always read its apertures 1/2 stop faster then it should be - 2.4 instead of 2.8, 6.3 instead of 8, etc. When the lens is in bayonet it doesn't have any luft.
  5. Well, I guess the major question is whether the issue is mechanical -- i.e., if something is preventing the pins on the lens mount and the lens from moving where they should, perhaps because of too much resistance on one or the other -- or if it's electronic, i.e. the camera sensor is not picking up the position of the lug in the lens mount.
    The only problem that I ever had similar to this was with the early production Contax 159MMs. These were the first Contaxes to have a program mode and therefore the first actually to read and manipulate the aperture setting. Often in these cameras the digital readout of the aperture was off by half a stop or so. My dad had to return the first couple he bought before he got an accurate one. I don't think it affected exposure, though.
    Are these lenses you are using multi-mode ones with the green minimum aperture and the lug for engaging the program modes? You mentioned Yashica lenses, AFAIK none of the had this lug and thus none were fully compatible with the Contax camers that had program modes. My understanding was that the Zeisses made prior to the multi-mode (pre-1986 or so) had aperture mechanisms that were heavier and more difficult for the camera to operate. Maybe that relates somehow to your problem.
  6. AS August mentioned. Only certain lens were capable or compatible. I believe those marked MM.
  7. I think the issue is mechanical. Otherwise, I would have such problem with all my lenses.
    As far as I know, all, MM and not-MM, lenses should be compatible with Contax RX. But only aperture priority and manual modes will work with not-MM. All my lenses are not-MM (I used Contax 139Q before buying RX and didn't need MM). But most of them work just fine with my Contaxes RX. Also, as I said before, all my Yashika lenses also work fine with RXs.
    I tried to play with pins on the lens mount of the "problematic" lenses - they are not as smooth as on other lenses. Also a lug responsible for transfer of diaphragm data from the lens to camera body, located on the camera bayonet (on a circlular detail under the external bayonet detail of the camera), on one of the RXs is not as smooth as on my 139Q.
  8. Guys, thanks for your answers!

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