Replacing Graflex Lens With Lens Not Containing Thorium

Discussion in 'Collector's Corner' started by BradenLH, Aug 17, 2017.

  1. BradenLH

    BradenLH TPF Noob!

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    Hello,

    I collect and restore old cameras, though a bit of a novice.
    Are there any modern (post 70s) that are compatible with graflex caneras? The large format lenses I have seem to be compatible as it fits nicely on the lens mount though the body cannot close due to the size of the front element.
    Being aware of thorium glass elements, especially Kodak ektar lenses, I would like to use a lens without thorium. I do keep all cameras as their original state and components, however I would prefer to use a modern lens with graflex cameras.
    I'm aware that the lenses do not pose a significant risk as the main concern are thorium eye pieces though I've come across many sites and forums debating the safety of such glass elements and their pose of radioactivity.

    With appreciation,
    Braden


     
  2. pendennis

    pendennis No longer a newbie, moving up!

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    Most any of the modern lenses can be mounted using the appropriate hole in the lens board. Yes, you can't close Speed Graphics using these lenses. I use a Sironar N 210mm f5.6 with my Super Graphic, and I dismount the lens when I close up the camera, or remount the Graflex 135mm f4.7 Optar. I also have a blank lens board I also use for storing the camera.

    There are potential issues with the focal length of the longer lenses and the draw on the bellows. There may not be enough draw on the SG's bellows for 300mm+ lenses, and you probably will not have nearly enough for close ups with some of the newer lenses.

    The lens board holes for Ilex shutters are not the same diameters as for Compur and Copal shutters. Here's a cross reference you may find useful.

    Lensboard Hole Sizes
     
  3. compur

    compur No longer a newbie, moving up!

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    The normal lenses supplied with the Graflex 4x5 cameras were mostly (if not all) 4-element “Tessar” type lenses which were quite compact. That's just the type of lenses the cameras were made for. You can certainly use other lenses having more elements, of course, but more elements = larger size lenses so you won't be able to latch up the bed with the larger lens in place. I don't think it's possible to stuff more than 4 elements in a lens without having it be substantially longer. And, those old 4x5 Tessars/Ektars pretty much disappeared along with the last of the Graflex press cameras in the 1970s as far as I know.

    I have seen Graflex cameras with a large hole drilled into the bed so that it could be folded up and latched with a larger lens in place. I'm not recommending that, BTW, I just thought it was funny. :)
     
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  4. Derrel

    Derrel Mr. Rain Cloud

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  5. compur

    compur No longer a newbie, moving up!

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    ^ That's a good reference, Derrel.

    Now that I think of it the Schneider Super Angulon 90/8 might fit the OP's requirements, especially if mounted on a recessed lens board. I don't know if that is a post-1970s lens but it's pretty compact.
     
  6. IanG

    IanG No longer a newbie, moving up!

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    I don't know of any normal Ektars used on Graphics that use Thorium glass, so it's really not an issue. Most Ektars are Tessar type designs, although the 203mm f7,7 Ektar is a Dialyte.

    Yes Aero Ektars use Thorium glass but these were designed for aerial surveillance work although some now use them as fast lenses on Speed Graphics but you need a custom made lens board to mount them so they are highly specialist. Thorium glass was only used for fast lenses and is a weak Alpha ray emitter, so weak they won't penetrate dead skin (which is the surface layer of skin) if you ingested the thorium glass then that's a different issue but damn near impossible :D

    We are all exposed to similar levels of cosmic Alpha radiation on a daily basis, there'a a lot of hype about so called radio-active lenses, if they were dangerous no-one would use them and there would be some serious articles warning about them.

    Ian
     
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