RB 180mm lens separtion

Discussion in 'Medium Format Cameras and Accessories' started by archphoto, Feb 27, 2009.

  1. archphoto

    archphoto Member

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    Dear members,

    I have have looking at ebay for a 180mm C lens for my RB 67.
    Quite a few have "lens separation" esp. on the rear element.
    Q:
    Does this affect the quality of the image ?
    Has anyone tried to repair this with Canada Balsem or equivilent and what were the results ?

    Thanks for your repley's.
    Peter
     
  2. keithwms

    keithwms Member

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    It's going to be hard to say how serious this problem is unless you have the lens in hand.

    Given the low price of these lenses why not go for one in excellent condition....
     
  3. EdColorado

    EdColorado Member

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    If you take a look in the APUG repair forum there is a thread on just this subject. Tells about glues and methods.

    Good luck,
     
  4. archphoto

    archphoto Member

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    Keith you are right with your last remark !
    Got my self last night an E+ 150mm SF C with every thing for a great price.....

    Ed, I will

    Peter
     
  5. paul ron

    paul ron Member

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    The RB67s 180mm lens has no rear cell. I haven't seen any with separation as of yet since the front cell is such a very well sealed unit.

    The 150mm is a very nice soft focus lens used mostly for studio portrait that should include discs to further soften the image to different degrees. A farily sharp image, with very little softening around the edges can be had at around f8.
     
    Last edited by a moderator: Feb 27, 2009
  6. archphoto

    archphoto Member

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    Thanks Paul, you gave me the answer I was looking for.
    What explains the discoloration at the outer rim of the rear element ? Damage to the coating, or just an optical illusion ?

    Do you, or somebody else have a chart for me with the drawings of the lenses ? (the optical system)
    I have looked at the site of Mamiya but to no avail.

    I got the 150SF with the 3 disks, both caps and a hood, looking forward to it, I hope it will be close to the Imagon that I have and love for 4x5 inch.
     
  7. paul ron

    paul ron Member

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  8. BrianShaw

    BrianShaw Member

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    You'll love it.
     
  9. paul ron

    paul ron Member

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    The RB 150 is one of the most romantic lenses out there. It was a standard lens in the studio for glamor n portrait, still life n product work. It has just the right amount of softness n is so clean.

    Oh Peter, you are probably seeing a relection in the 180mm rear. There is a frame mask at the back n maybe you're getting confused by it? Most 180s I've seen are in great shape, rarely see any bad glass.
     
  10. archphoto

    archphoto Member

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    Paul: the 180 has a rear cell: look at the scematic you gave me.
    Probably go for an E+ one when I need it, I first have to try out that 150.......

    Thank's !

    Peter
     
    Last edited by a moderator: Feb 28, 2009
  11. Q.G.

    Q.G. Inactive

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    The schematic shows no elements behind the aperture (the two vertical stripes). So no rear cell.
     
  12. archphoto

    archphoto Member

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    This lens is a bit unusual in its build: the entrire optical group is in front of the shutter/apperture.

    In this way the "rear"cell is in front of it.
     
    Last edited by a moderator: Feb 28, 2009
  13. paul ron

    paul ron Member

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    Peter, I service these 180s all the time n can tell you for certain, there is no rear cell. The entire front cell, everythnig in front of the shutter, comes out like a light bulb, completely hermetically sealed.

    In all the years, I have never had any with lens separation. They may be fungus eatten or scratched but never separated. I should crack an old one open to see if they have any glued elements at all. I wonder? They are really built like hand grenades.