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Thread: Make your own helical focus mount

  1. #21
    Steve Smith's Avatar
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    Re: Make your own helical focus mount

    Here is my contribution. Some of you may have seen this before.

    http://stevesmithphoto.webs.com/pano612.html


    Steve.

  2. #22
    jp's Avatar
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    Re: Make your own helical focus mount

    The ebay $125 helical mount I have. I haven't measured it with calipers but I'd guess it allows about 3/8" upto 10mm of focus adjustment range. It's not huge, but should be fine for wide angle adjustment as long as you are not trying to do closeups. I bought it to allow more lens options on my gowland aerial (every lens has a different flange distane) and it will suit that purpose fine. They were willing to provide one without the preprinted stuff that shows on the ebay auction.

    The focus is fairly stiff at first and should not come out of adjustment accidentally. For casual focusing one might want to add a grippy rubber band or otherwise textured surface. It comes as black aluminum.

  3. #23
    8x10, 5x7, 4x5, et al Leigh's Avatar
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    Re: Make your own helical focus mount

    As I mentioned previously, I have a selection of NOS helicoids from 35mm zoom lenses.

    Here's a drawing of one type: http://www.mayadate.org/pix/VivHel01.pdf

    ... and his pic:



    This one has a clear ID of ~2" and a throw of ~1". Other types are about the same diameter, but with longer or shorter throws and slightly different configurations.

    These are factory assembled and lubricated, each in its own little plastic bag.

    Note that these are internal lens components that will require additional parts for a complete functional installation.

    Let me know if there's any interest.

    - Leigh

  4. #24

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    Re: Make your own helical focus mount

    Pentax 6x7 lenses are pretty darn big. Some of them take 82mm filters, if you can find an Ugly one and take the glass out and other unnecessary bits out they could work for 65mm I think. The problem could be there are mostly long though- finding one short enough to use for wide angle lenses could be difficult.

  5. #25
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    Re: Make your own helical focus mount

    Here's something I thought of, and this might be slightly OT:

    Bronica, some Pentax, and I think Hasselblads, have lenses with in-lens leaf shutters. Is there any way to trigger these lens' shutters? If so, you could make a box camera and have full focusing capability along with in-lens shutter. But it would only cover medium format, but still.
    Science is what we understand well enough to explain to a computer. Art is everything else we do.
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  6. #26
    8x10, 5x7, 4x5, et al Leigh's Avatar
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    Lightbulb Re: Make your own helical focus mount

    Quote Originally Posted by BetterSense View Post
    ...Hasselblads, have lenses with in-lens leaf shutters. Is there any way to trigger these lens' shutters?
    It would be difficult.

    The Hasselblad shutter cock and release functions are controlled by a rotating shaft in the camera body, aligned coaxially with the lens.

    Duplicating its operation would be a challenge, but not impossible.

    - Leigh
    Last edited by Leigh; 12-Jan-2011 at 18:17.

  7. #27
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    Re: Make your own helical focus mount

    I was hoping it was something as simple as a cable release socket. I'm pretty sure I've seen a Pentax 6x7 camera that had lens with a cable release socket directly on it.
    Science is what we understand well enough to explain to a computer. Art is everything else we do.
    --A=B by Petkovšek et. al.

  8. #28
    Steve Smith's Avatar
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    Re: Make your own helical focus mount

    Quote Originally Posted by BetterSense View Post
    Here's something I thought of, and this might be slightly OT:

    Bronica, some Pentax, and I think Hasselblads, have lenses with in-lens leaf shutters.
    It took all of my powers of self control not to take one of my Bronica ETRS lenses apart to use the helical. I tried to find a broken one for sale but couldn't. I think they are big enough to take most LF lenses and as the focus ring is at the body end, most of the superfluous lens stuff can be removed.


    I would still like to try one so if anyone has a broken ETRS or SQ lens they would like to get rid of, let me know.


    Steve.

  9. #29

    Re: Make your own helical focus mount

    I've used the Fotoman Helical to build a camera and think they are well made a very good value for the money. Here is the link:http://www.fotomancamera.com/accessories_list.asp

    If you can scrounge a helical and don't mind the work of adapting it - great. I've done that too, but in this case a client was paying my machining time and a stock helical saved him quite a bit.

    Cheers,
    Bill

  10. #30
    Jeicob's Avatar
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    Re: Make your own helical focus mount

    Some 40 years ago my father build this and I've been told that helical itself came from a Bronica
    (the hard part should have been the screw in mounting on the front plate keeping infinity at top and all)


    SA 47/5.6 with Graflex (Graflock?) back and cassettes for 6x9, 6x7 and 6x6. The helical will focus from infinity down to one feet.
    It's now obsolete as I recently bought a Sinar Handy and it will be up for sale if anybody would be interested to buy or trade!
    The empty frame could be used to create a front/body for other lenses

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