Strange prob, cannot focus Schneider 50mm on Durst M605, yet my 2 other 50mm's will!!

Discussion in 'Enlarging' started by gamincurieux, Jan 21, 2009.

  1. gamincurieux

    gamincurieux Subscriber

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    When the head is extended right to the top of the column, I cannot focus my Schneider 50mm on my Durst M605. The recessed Siriotub lensboard is correct for the lens. If I swap over to either of my Nikon or Fujinon 50mm lenses I don't have a problem focussing, again same height etc - admittedly the bellows are aaaaalmost fully closed up with these two as well, but I can focus, there's some play on the bellows. Put that damn Schneider back on and I can't focus, the bellows are fully closed up. It's really got me, cannot figure out why. The lens is fine, does the job ok when lower down the column. Does anyone have any idea about what might be the problem? I've heard about some lenses being higher than others, but really, I would not expect there to be any difference whatsoever between two standard Nikon & Schneider lenses.

    Yours in frustration,

    Paul
     
  2. waileong

    waileong Member

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    You probably need a retaining ring.
     
  3. Mark Fisher

    Mark Fisher Subscriber

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    My guess is that the actual focal length is different between the different "50mm" lenses. If it is 48 or 52mm could make a big enough difference. The only other thing I can think of is that there could be a spacer or an additional retaining ring on the Schneider effectively increasing the bellows extension.
     
  4. Vinylman

    Vinylman Member

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    Try putting the lensboard in the other way round. I did this once myself.
    Phil
     
  5. Nick Zentena

    Nick Zentena Member

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    You sure it's not the Nikon that doesn't work? Nikons have a long flange distance. The Schneider must be longer then the other two. Unless Durst makes a deeper board you might be out of luck. Use a longer lens if you have it.
     
  6. youngrichard

    youngrichard Member

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    Flange to infinity focus distance

    As noted in previous post, it is the Flange to Infinity Focus Distance that is the problem. If you go to the manufacturers' websites, that measurement will be in the detailed spec somewhere. I had the same problem with a Durst DA 900; just couldn't get the lens I wanted to use close enough to the negative; there was no space to fit a deeper lens board. Researched lens flange to infinity focus for several lenses, and found they can vary by just 2 or 3 mm, but enough to stop focussing on big enlargements when the bellows are squeezed.
    Richard
     
  7. gamincurieux

    gamincurieux Subscriber

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    And now another problem, albeit not a huge one. I have just picked up a Rodenstock Rodagon 50mm 2.8, the older style with the silver knobs around it.

    It sits so far into the Siriotub that I cannot see the red/green glowing aperture numbers.

    However, I CAN focus it.... unlike the Schneider problem above. I've since gotten rid of the Schneider anyway, no love lost. That leaves me with the Nikon/Rodenstock/Fujinon, that's quite enough!

    But this not being able to see the illuminated aperture setting on the Rodagon because it is obscured by the Siriotub, has anyone else noticed this & have you been able to do anything about it???

    I never for a moment envisaged having hassles of any kind with any lens on the M605!!!

    I mean, sure I can count, I'll be able to use it (haven't as yet:wink:, but I would still like to be able to see it like I can easily with the Nikon (the Fujinon's aperture is not illuminated).

    And, about the Fujinar, does anyone know anything about them? Formally it's the FUJINAR-E 1:4.5 f=5cm.... with the brown aperture ring & black aperture locking ring..... not much info at all out there about these.
     
  8. gamincurieux

    gamincurieux Subscriber

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    That's FUJINAR, not Fujinon :wink: