Zenzanon MC 75mm f2.8 stuck blades

Discussion in 'Medium Format' started by anmol_mishra, Jul 11, 2010.

  1. The 2 aperture levers do not move all theway anymore.
    There are 3 pics here
    First pic shows f5.6
    Second pic shows the shutter at that aperture. Note that the first shutter is at 5.6 while the second one is closed off.
    Third pic shows the shutter at wide open aperture. Note that the first shutter is open while the second one is still closed.
    I reassembled the lens - and I know I did it right as the infinity aligns with the marker. Also, I can change the iris. [​IMG] Also I used up ALL the screws so its all great. However, now there seems to be 2x iris'es, one which is permanently closed and the other that can open and close as needed.
    So no light is entering my lens at all. Any idea what I may have done ? There is a small part of a spring that may have fallen from this assembly as well. [​IMG]
  2. One is the shutter. The other is the iris diaphragm.
    Probably, before reassembly you did not properly line up the actuator that is moved by one of the pins. Take it apart and try again. Look for the broken spring. If there is one, and you can't find a replacement, you're best off just replacing the lens. They're not expensive.
  3. Hi Jeff. There is indeed a broken spring. Nice pick. This was my first DIY lens disassembly project. So I would be keen to try to fix it.Is there a way I could force the shutter to be always open ?
    I can use the aperture to adjust the iris and use the lens in manual mode ?
  4. If those pins don't move the camera cannot operate. It will just stop. Even more serious, if you make the shutter stay open all the time you have no shutter. The only way that could work is if you only take pictures at night with very long exposures, and use the lens cap or such to cut off light.
    If you really want to force it to stay open, first see if the A/T lever on the lens will work on T (Time). Without the spring it might not work.
    I still think you put it together wrong if the pins don't move through their entire travel. And if they don't the camera mechanism will just stop without raising the mirror.
    You could possibly get a spring from Koh's Camera.
    BTW, that looks like an EII lens, not an MC, judging by the 62mm filter thread, the hood bayonet and the green stripe. I have the same lens. When it stopped working I took it apart to where I could clean and relube the actuating mechanisms that the pins on the back move, which restored full function.
  5. Hi Jeff. I am not using this lens with a Medium Format but with a 35mm DSLR. So the shutter is not important as I use the DSLR shutter.
    All I really need is the shutter out of the way.
    And you correct - it is a Zenzanon EII. It says so on the green stripe.
  6. Then try the T/A switch on the lens. If the shutter still won't open, I am fairly sure if you take it apart again you'll figure out what to do. Good luck and have fun!
    By the way, how are you using it? Just straight on as say, a portrait lens, or as a tilt/shift? Those 75's are so cheap now I can see no reason not to experiment if one is so inclined.
  7. I am using it as a tilt/shift lens with a rubber toilet plunger :) There is another camera swap meet in Sydney next Sunday so hopefully I can pickup more fungused lenses..

  8. Hi everyone,

    I have problem with leaf shutter of zenzanon EII 75 f2.8. Sometimes shutter works fine, but sometimes stays closed and doesnt open up. I tried to move focus ring when shutter is closed (closed after shoot) and then shutter opened up. I test body with my zenzanon 150 f3.5 and everything is ok. I think that this is a problem with leaf shutter. Should I try CLA in service for this problem? Maybe problem is deep and this lens need to change leaf shutter.

    I will be very greatful for any help.


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