Copal No.3 - with lens?

Discussion in 'Large Format Cameras and Accessories' started by masimix, May 5, 2011.

  1. masimix

    masimix Member

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    This is a newbie question, and since I know little about LF, I hope someone can clear this out for me.

    I found in the studio (on the loft) a box with a large format lens, but is it a fully working lens, or only the shutter? It is a Copal No.3, and it has a rear glass element which can be unscrewed. I put a white paper behind and it sure makes a picture, it seems to cover 8x10, but I can not really tell.

    I'll post some photos of it here, and hopefully someone can tell me if I can go ahead and buy a 8x10 camera and start learning:wink:

    Thanks in advance,

    Marius

    [​IMG]

    more photos:

    http://mariushauge.no/copal/copal_no31.jpg
    http://mariushauge.no/copal/copal_no32.jpg
    http://mariushauge.no/copal/copal_no33.jpg
    http://mariushauge.no/copal/copal_no34.jpg
    http://mariushauge.no/copal/copal_no35.jpg
     
  2. vpwphoto

    vpwphoto Member

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    Imagon... is that the only perforated disk you have found?

    It's a soft focus lens, I think they still make them. This one looks pretty new.

    Are you selling? Google Imagon and you will learn more.
     
  3. masimix

    masimix Member

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    Soft focus, alright. It is the only disc, yes. Can the lens be used without this? As you can see from the other photos (link), it can be removed. I have no plans to sell this, no..

    edit: there is no glass in front of the shutter, only behind.
     
  4. Ole

    Ole Moderator Staff Member Moderator

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    The Imagon only has glass behind the shutter, so it's exactly as it should be.

    Without the disc the image is very soft, with the disc slightly less so. There are several different discs giving different softness sold with these lenses, which is why everyone wants to know if you have the full set or not.
     
  5. ic-racer

    ic-racer Member

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    Nice find!
     
  6. johnielvis

    johnielvis Member

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    Seems to me it's fully functional since there's a working aperture in the shutter---you can dial in as much sharpness as you want by stopping down the iris

    keep it for sure---I would
     
  7. masimix

    masimix Member

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    Thank you all for the information! I've googled it, and understand a little more now. What I don't get is how to measure exposure without an aperture indicator. The aperture works, as seen on this picture:
    [​IMG]

    I guess I'll have to learn more about LF-photography. I went to one workshop once, together with Ole Tjugen over here actually, husker du, Oslo ca. 2004/2005? He was already experienced, I remember beautiful slides from the west coast. There was something about measuring light right at the back, where the filmplane is?

    Anyway, I'm going to NYC in a week, and have checked out B&H and Adorama for used cameras. Maybe I'll bring the lens and find a camera? Before that, I'll read more on largeformatphotography.info and apug:smile:
     
  8. vpwphoto

    vpwphoto Member

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    The disks ARE the F stops.. I think you have the f 6.? There are an f8, and f11 possibly 16...
     
  9. Ole

    Ole Moderator Staff Member Moderator

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    Hallo Marius - joda, jeg husker!

    Any camera which takes Technika boards can take that lens and board, except if the front standard is so thick it interferes with the shutter.

    For cameras which use larger lens boards there is usually a Technika adapter available, too. But on the other hand, putting the lens on a different board is very easy. All you need is a board with a hole the right size, and the Copal 3 is a standard size.
     
  10. masimix

    masimix Member

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    Yes, the discs are f-stops, obviously, the H-numbers (H=7.7&9.5) can be transferred to f-numbers. I found a link to a thread here on apug about it http://www.apug.org/forums/archive/index.php/t-31787.html. But one can also stop down via an aperture ring, and how to measure this.. Must be by measuring the light falling right on the filmplane. Or? For instance, if I take the ring of, for maximum softness, what is the f-stop then?

    Thanks all for the replies, I'll try to read more about the lens, and I'll take it with me to NYC next week. I want to buy a used 4x5" and maybe they can provide som information on B&H or elsewhere, I've been to B&H a couple of times, someone always knows there..

    But do keep on posting info on this, if you have!
     
  11. Ole

    Ole Moderator Staff Member Moderator

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    That one is very very simple to determine the f-stops on:

    The lens focal length is 300m, that is clearly marked on it.

    The f-stop is the diameter of the effective aperture divided by the focal length - or to get the f-number, take 300mm/diameter. Since there is no glass in front of the aperture, the effective diameter of the entrance pupil is identical to the diameter of the aperture opening - as a circle, but the aperture is close enough to a circle to make the difference negligible.

    Simply measure the size of the opening, and divide 300 by that number in mm. I have a cheap plastic measuring thingy which is perfect for the purpose - I think I bought it in Clas Olson. :smile:
     
  12. Two23

    Two23 Member

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    I have the 250mm Imagon. As I recall, the lens is f4.5 without any disks in it. The lens was made in several lengths. The 200mm was used on medium format, the 250mm on 4x5, the 300mm covers 5x7, and the 360mm covers 8x10. This seems to be a challenging lens to learn, but then again I don't shoot portraits and have been using it for b&w landscapes.


    Kent in SD
     
  13. masimix

    masimix Member

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    So Ole, in norwegian:

    Jeg måler diameteren på åpningen og deler 300 på tallet? F.eks, full åpning er ca 40mm - 300/40=7,5 - f7,5. Minimum åpning ca 2mm - f150..?

    And what if the disc is still on, should be extremely little light passing through?
     
  14. Ole

    Ole Moderator Staff Member Moderator

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    det stemmer, det! Med disken på, blir det mer komplisert: Husk at åpningen der er konstant, så du skal IKKE addere. Hvis blenderåpningen er mindre enn hullet i skiven er det blenderen som dominerer, hvis blenderen er mer åpen er det skiven som dominerer. Ekstra ille blir det hvis blenderåpningen dekker deler as de ytre hullene! Det ekleste er nok å bruke den ene eller den andre, ikke begge samtidig...
     
  15. masimix

    masimix Member

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    Okei, takk, da sier vi det, enten den ene eller andre.. Det holder med discen regner jeg med.