Mamiya Sekor Z 50mm ULD repair

Discussion in 'Medium Format' started by rupa_sztraka|1, Jul 14, 2021.

  1. Hi, i pulled apart the rear group of elements on my 50mm ULD to clean severe fungus growth. Stupidly i cant remember the order the elements go back together & its not very self explanatory as in the group can go back together many different ways. I need a diagram showing what order & orientation each element goes back together but nowhere on the net is there a diagram of any kind.

    Any advice appreciated!
  2. c50.jpg
    I need something like this but for 50mm ULD
    Does anybody have access to the Repair Manual for Sekor Z lenses that can send me a Photo or Scan?
    Last edited: Jul 14, 2021
  3. Someone may know, but perhaps the quickest way to find out would be to reassemble the lens, attach it to the camera and note any softness/blurriness. The danger in this though is that if any elements are the wrong way around, they could bind on something and prevent final tightening. The front and rear elements should be self-explanatory while the middle elements might be the ones that need some trial and error.
  4. This link might help.

    If you scroll to the bottom of the RZ lenses manual, you'll find optical diagrams next to the lenses pictured.

    Don't forget to donate to Mr Butkus if it answers your question.
    kmac likes this.
  5. Good find.

    I think this is the lens: ⓶ Z 50mm f4.5W ....
    in this manual .... .... scroll 3/4 the way down

    Unfortunately the diagram of the lens construction is quite small, but zooming in helps a little to see it better.
  6. Thanks for that info & links. Unfortunately the only 50mm lens in that manual has a different lens construction than what i have. My lens the "ULD" has an adjustable floating element. I am very confused as i have tried assembling the lens almost every possible way that makes any sense but when i put it on the camera & view through it the image is full of halos & soft focus areas is the best way to describe it. Is it possible that when i was cleaning the elements i rubbed off some special coating or something? :(
  7. Try this link for the floating element 50mm lens. The lens construction is much clearer ....

    You may have disturbed the accuracy of the floating ring adjusting mechanism, that's the only thing I can think of just off hand. That floating element may have to be synchronized properly with the focusing elements to attain sharp focusing when using that 50mm lens.

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