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  1. #1
    Prest_400's Avatar
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    Zuiko OM 50mm 1.8 fell, hard to mount

    Hi there,

    About half an hour ago I was cleaning my OM-1 and unmounted the lens. Left it in front of me, slightly close to the edge of my desk. Didn't take too long until I knocked it and... bang. 3 feet into the hard tile floor, including some rolling on the floor.

    I was horrified by the sight (my good old poor lens, who accompained me on trips) but the lens seemed fine. It had a filter plus a hood but the rear element was unprotected... All of them fine. Diaphragm works well, all well... Heck, it even seems to have a smoother focus!

    Except mounting... It sticks halfway, requiring superhuman force to successfully mount. I forced it a bit and I find it can be mounted and unmounted but requires a brutal level of force. I Mounted another lens on the camera and that one is fine.
    I am intrigued by this, I thoroughly checked the bayonet and it looks alright; nothing bent. Rear lens cap works fine.
    I can feel that halfway into the mounting, the bayonet lock begins to act. But I have no idea of what can let it lock in such a strong and premature way.

    And while we're at it... The camera works fine, but I find that the higher speeds (60-1000) have weak clicks, with little resistance while switching them. The slow speeds are fine and with a rougher touch. It sat for a couple of years with very intermittent use.

  2. #2
    shutterfinger's Avatar
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    Something is bent somewhere. Stand the lens on its front on a smooth flat surface. Lay a rigid straight edge across the center of the lens rear. Using a caliper or fine graduation ruler measure from the straight edge to the work surface on both sides of the lens. Rotate the straight edge 30° and remeasure, repeat until you have a measurement for the full circumference of the lens. A thin metal ruler on edge makes a good straight edge. Expect a .050 to .1 inch variance minimum to cause the problem. If all measurements are equal or less than .010 variance then measure the diameter of the lock ring on the lens every 30° to find if a bent section exists there. 30° is 5 minutes on a clock/watch face. Post a picture of the lens mount side of the lens. The shutter click and dial suggest its time to have a CLA done on the body.
    1/64=.0156
    1/32=.03125
    1/16=.0625
    1/8=.125

  3. #3

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    you bent the mount. buy another lens and be more careful next time.

  4. #4

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    Indeed the mount is bent. It only takes a couple of degrees to bind.
    Shutterfingers check is the way to go, but if the lens otherwise works; the bent section
    can be straightened (DUCK) with a large screwdriver twisted between the offending part and surface of the mount.

    Be aware! You will find some later responses to this statement using the following terms. :o)

    SACRILEGE..HEATHEN..BARBARIAN..BRUTE! ...............You'll ruin the alignment/focus/value/etc of the lens.
    Heavily sedated for your protection.

  5. #5
    Prest_400's Avatar
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    Sorry for not replying before. Have got so much work and study to do and even cleaning cameras is a nice distraction!

    It still requires brute force but after mounting and unmounting a few times and letting it sit overnight it isn't as much as before.
    I might try the screwdriver trick... By the way, trying to unscrew the mount is about impossible, none of the screws will unscrew! The older 28 and 135 will, but this one not... It's as if they were superglued.
    Rebending, I tried a couple of soft hits to the table, won't do it for the moment.
    And once I need something properly measured or repaired I feel it, almost no proper tools! I tried measuring as per shutterfinger but A steel ruler can't get close into the mount and depending on the viewpoint one sees a differnt measuring mark.

    Given that I tend to use mostly this lens, I don't need to change it that much and at the moment it's alright. Functionally it's fine, good focus and fine diaphragm. The problem is IF the lens has become misaligned... Seemingly not, infinity focus is fine when focusing through the viewfinder.
    These older systems are tanks, anyways

  6. #6
    shutterfinger's Avatar
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    Warm metal bends/reforms more easily than cold metal. Warm your oven on its lowest temperature setting then turn off once the oven reaches temperature and sit the lens in the center of the oven for 15 to 20 minutes. Be sure to remove the lens caps and filters. Sitting the lens in direct sun for an hour or so will warm it up also.

    I will not hazard a guess as how reform until I see how it is bent. I would be cautious trying some tricks as the metal can crack or break.

    Accurate measurements are not easy on cameras.

    The screws are most likely sealed with a thread locker that requires a special solvent to loosen that is used by Olympus and their service centers only.

    I routinely fix large and medium format cameras, their accessories, and shutters. A bent mount is within my abilities and is something I would tackle on 35mm gear while a body CLA is not.

  7. #7
    Poisson Du Jour's Avatar
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    The rear mount has been buckled out of true, hence the higher resistance you are feeling when mounting; I would suspect a lens falling onto a hard floor would also be affected by misalignment of one or more elements, even though that may not be immediately visible to the eye. I would advise against mounting it anymore lest you impart damage to the camera's mount (scoring, chiefly).
    .::Gary Rowan Higgins

    A comfort zone is a wonderful place. But nothing ever grows there.
    —Anon.






  8. #8

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    Quote Originally Posted by summicron1 View Post
    you bent the mount. buy another lens and be more careful next time.
    +100.
    And, constant fiddling putting it on and off the camera will likely damage that, too. "...superhuman force to succesfully mount..." This is always a sign to stop what you are doing.

  9. #9
    baachitraka's Avatar
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    Please do not destroy the camera. Get an another 50mm.
    OM-1n: Do I need to own a Leica?
    Rolleicord Va: Humble.
    Holga 120GFN: Amazingly simple yet it produces outstanding negatives to print.

  10. #10

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    Please. When you bend something in the repair trade it's called "reforming". That way you can charge more for it.

    Anyway, One ear of the lens mount was most likely slightly bent toward the lens, not away from it. That's why the screwdriver,
    crude as it is should work.
    Heavily sedated for your protection.

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