mamiya rb67 out of focus

Discussion in 'Medium Format Cameras and Accessories' started by geoffdodd, Feb 22, 2013.

  1. geoffdodd

    geoffdodd Member

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    I've been running a few tests on my Mamiya RB67 Pro-S lately and for some reason, my images are slightly out of focus. The lenses (90mm and 180mm 'C' lenses) are both clean, front and back. My images in the past have always been sharp. But these last three rolls look mildly out of focus, as though nothing is in focus. The only thing I think it could be, is I don't mount the lens very tightly, only because they can be wretched to remove if too tight. Any thoughts?
     
  2. rjs003

    rjs003 Subscriber

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    Back attached properly?
     
  3. Marc B.

    Marc B. Member

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    Film back...as mentioned, or focusing screen not properly/fully seated(?).
    I doubt it's your lenses. Remember...it's a bellows focusing camera.
    Even if your lenses were loose, you would still see a focused image.

    Marc
     
  4. MattKing

    MattKing Subscriber

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    If the problem isn't focussing error, but instead overall lack of sharpness, than the likely culprits are lens damage or camera (or subject) movement.
     
  5. paul ron

    paul ron Member

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    Use a ground glass on the film plane to check it to be sure...

    wear glasses? maybe a diopter problem or you aren't aligning your eyes n glasses properly when focusing?

    Are you focusing in preview stopped down?

    Look through the lens to be sure it is clean?

    Also alot of people don't realize it takes a split second after the mirror comes up for the shutter to fire.. are you waiting n holding the extra split second?

    .
     
  6. geoffdodd

    geoffdodd Member

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    I ran another set of tests last night, this time being scrupulous with getting the focus, locking it and using the mirror up. Seemed to work better.
     
  7. paul ron

    paul ron Member

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    Ya know I also have a problem with sharpness sometimes till I really looked closer at what I was doing.. The focus lock has become a habbit now.. it seems as you press teh fire button the rack moves ever so slightly.. cured me.. maybe that was it after all?


    glad you found the solution though.

    enjoy your RB.
     
  8. M Carter

    M Carter Member

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    One key issue - are you seeing good focus in the viewfinder, but not on the film? With these old cameras, the foam parts are usually crumbled away. The piece of foam beneath the mirror is a key part - if something prevents the mirror tray from resting on the metal studs, you'll never get good focus. Might check for foam crap in the main camera box that could be clogging things up, or if the camera has been re-foamed, make sure the mirror makes a solid metallic "clank" when lifted (with a fingertip through the lens opening) and dropped.

    Though it sounds like your issue may have been mirror slap, if mirror-up has solved your problem.

    I had a focus issue using strobes - realized the shutter was stuck open and the modeling lights were giving me a ghost image as I cocked the camera.
     
  9. paul ron

    paul ron Member

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    RBs shouldn't have mirror slap if the bumpers are properly installed n sized.. a common DIY mistake. There is a strip of foam under the mirror.. that stops the other flap dead.

    2 square bumpers (one is larger than the other, takes up the slant of the mirror), just under the front top lip of the mirror box...those are to stop the mirror dead n keep it from reverberating.

    If you had the bellows off, this becomes more apparent.. but not many get that oportunity to see it function n just replace em as if they are light seals.

    But whatever you did to cure your problem is the correct solution.. everyone has a differet way of doing it and the end result, the pictures, is where it counts most.