Chinese focusing helicals for Linhof boards

Discussion in 'Large Format Cameras and Accessories' started by David A. Goldfarb, Oct 18, 2010.

  1. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    I've seen various focusing helicals made in China for sale on eBay over the last few years, and I just bought one from a seller named "jinfinance," and I received it, and I'm very impressed. It's really a nice piece of machine work. They advertise it for a 65mm lens--

    http://cgi.ebay.com/WIDE-ANGLE-DEVI...511?pt=LH_DefaultDomain_0&hash=item20b44cf7bf

    I asked them if I could have it engraved with a scale for a 47mm lens, so I could use it with my 47mm S-A XL, and it works perfectly. It focuses to infinity, and it focuses to 0.4m, and of course one could focus closer by moving the lensboard forward. It also doesn't vignette in the vertical orientation on my 4x5" Tech V with the bed dropped two notches.

    The only thing missing is an index mark on the board for the focus scale, but that's something I could add myself easily enough, and if I actually want to use the scale, I either have to manually slide the front standard to the infinity focus point while checking the groundglass with a loupe, or I could make an index mark on the rail, since the standard has to be inside the box, where it isn't possible to put infinity stops. In practice, I'll probably be focusing mainly with a loupe on the groundglass, in which case it doesn't need to be exactly aligned at infinity, but it's nice to have the option.
     
  2. Mainecoonmaniac

    Mainecoonmaniac Subscriber

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  3. Curt

    Curt Subscriber

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    David, was this adapter designed for cameras that didn't have a camera built or built in focus and what does it give you that the Linhof focusing doesn't. I guess I'm no clear on the use. Is it for a finer focusing mechanism.

    Curt
     
  4. Steve Smith

    Steve Smith Subscriber

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    Nice but still a bit expensive for me although less than half the price of those available in the UK. See my 6x12 camera link below for my solution.


    Steve.
     
  5. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    The widest lens that works on a Tech IV/V/MT is 72mm on the main focusing rail. Wider than that requires the Linhof Wideangle Focusing Device, which I have, but the widest lens I could use with that is 53mm. This helical, or a much more expensive Schneider helical lets me use a 47mm lens on my TechV.
     
  6. Bob Eskridge

    Bob Eskridge Member

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    I purchased one for my 5X7 P&S project. I believe the design and quality is adequate but not equal to the Schneider product (which costs much more.)

    I believe the lack of infinity mark on the board is on purpose. It allows a little adjustment when first setting the infinity on a camera that you can set up for infinity with stops. (At least for my built-from-scratch P&S project camera I was happy.)
     
  7. Curt

    Curt Subscriber

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    I believe I see what the use is, some use it for making a P&S cameras and others use it on cameras were the standard rail can't work.
     
  8. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    Yes. If you think about how a folding press camera works, you've got a focusing rail on the bed, and then a rail inside the box that doesn't usually move, except on a camera like the Tech 2000 or 3000, where the front standard sits when the camera is folded. The helical or the wideangle focusing device lets you focus the lens while the standard is all the way inside the camera body on the fixed rail, as close as it can get to the film.
     
  9. Curt

    Curt Subscriber

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    Thanks David, now I get it, I have a Busch 23 and I see what you are talking about, the Linhof is much nicer and of greater precision of course.
     
  10. premo

    premo Member

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    As for a focusing scale, I read in some antique Ansco book a simple technique. They set up a series of candles at the various distances, focused the ground glass on each candle to make sure the focusing scale was on the mark. You could set the lens focus at the midpoint of the screw, set focus off the bed scale, then fine focus with the screw focus, if you wanted to.
     
  11. edp

    edp Member

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    I bought one of these (partly prompted by the recommendation here) and it is a nicely-made thing.

    It's a little bit bigger than I anticipated, and it's going to turn my planned 6x17 camera into a bit of a tank, but I'm one step closer to completing it and who ever heard of a compact 6x17 camera?