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  1. #1

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    Will sluggish aperture blades affect my pictures?

    I bought a 50mm Olympus OM lens to use on my "extreme conditions" OM 1. The aperture blades are a little sluggish to retract after a shot has been taken but I can't see any oil on the blades so I'm assuming a small spring or some other part is just a bit old and worn. Will this condition have any effect on my pictures? Can it be cheaply fixed?

    The seller pointed out this "condition" with the blades in his ad so I knew what I was buying and the lens was priced accordingly. It's basically a sacrificial lens for extreme conditions so it's not crucial that it functions flawlessly, but if it will affect my pictures then I might get it repaired if it's a relatively easy job.

  2. #2
    darinwc's Avatar
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    blades that are slow to close will definitely cause problems in bright situations. If they are a bit slow to open, then no that is not a problem. However you have to wonder why they are slow to re-open and perhaps the lag when closing is not as noticeable.

  3. #3
    Ian Grant's Avatar
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    If the blades close fast enough there's no problem, sluggish re-opening will have no effect on the exposures. What can be a problem is if the blades don't close consistently to the same aperture, I had a CZJ Pancolor that was inconsistent. Getting the lens repaired may well cost more than another secon=hand lens.

    Ian

  4. #4
    Steve Smith's Avatar
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    It may also depend on the way the OM stops down the lens. I don't know about OM cameras but some of my M42 bodies stop down the lens on the initial push of the shutter and fire at the end of the shutter movement.

    If the OM does this then a short delay between a half push and the final push should ensure the blades are fully stopped down.



    Steve.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  5. #5
    Rol_Lei Nut's Avatar
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    Even if the blades closing is sluggish, it should have no effect at full aperture (or close to).
    For other apertures, you can always manually close them (DOF preview) before shooting.

    Test: Open the back of your camera, close your lens to the smallest aperture and look through the back while holding the shutter open with "B". Remember the size of the diaphragm opening. Then, still looking through the back, fire the shutter repeatedly at various speeds and see if the diaphragm opening looks exactly the same size. That will give you an idea of how it might affect your pictures.
    M6, SL, SL2, R5, P6x7, SL3003, SL35-E, F, F2, FM, FE-2, Varex IIa

  6. #6

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    I have a Mamiya Sekor 50/1.4 that I use on a spottie. It stops down OK but opens back up slowly. It works fine. The pics are exposed as they should be. As long as it stops down quickly, you won't notice the delay in opening back up.
    Rick Jason.
    "I'm still developing"

  7. #7
    eddym's Avatar
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    Have you made any exposures with the camera? If so, do the photos show any evidence of exposure problems?
    If not... try it!
    Eddy McDonald
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    Eschew defenestration!

  8. #8
    Nicholas Lindan's Avatar
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    If the blades are slow you probably have goo/lube somewhere where it isn't supposed to be.

    This goo may become thick enough in cold weather to effect closing speed.
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  9. #9

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    The migrated oil may be in the rear rings or in the parts of the blade mechanism that you can not see. All those parts must be bone dry to work properly. John

  10. #10

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    Quote Originally Posted by Rol_Lei Nut View Post
    Even if the blades closing is sluggish, it should have no effect at full aperture (or close to).
    It should indeed.

    If you set, say, f/2.8 on an f/2 lens, and the aperture blades don't close fast enough, you end up with (worse case) a full stop overexposure.

    But it's true that if you set f/22, the overexposure will be much worse.

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