semi delimma....

Discussion in 'Large Format Cameras and Accessories' started by scootermm, Oct 4, 2004.

  1. scootermm

    scootermm Subscriber

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    alright so Im having some issues with my ancient 8x10.
    Ive attached an image to show the problem....
    The equipment. an 8x10 empire state wooden field camera circa maybe 1905. 2 8x10 gundlach film holders that are likely about as old as the camera, and a 12 inch wollensak velostigmat f6.3 barrel lens.
    Im getting some strange light pollution that runs along the 10 inch vertical. Im at a loss as to what is causing it. Sadly I think it could be a whole slew of different things.....
    where the holders meet the back....
    the film holders themselves......
    my lens maybe....
    perhaps the lenscap method of exposure Im using (although I cant see how this would be the cause as the light pollution as you can see the problem isnt on either side its more in the middle running up)
    Im thinking it might be the area where the film holders go underneath the springback and light might perhaps be sneaking in that way. Although that doesnt seem to make much sense since the light over exposure seems to be "floating" in the middle of the frame.....
    I make a habit of always keeping my dark cloth draped over the bellows between the front and back standards to help assist in reducing and straylight that might leak in from the bellows and any minor pinholes in there.
    Perhaps its the lens and some sort of aberation with the elements or weird flaring etc..... any advice or tips anyone might have would be greatly appreciated.
    its getting me somewhat frustrated but I just want to work and make the effort to remedy the camera and get it into working proper order.
    I cant send it to anyone as I dont have the money for that method at present.

    thanks in advance and I really hope someone has some tips etc....
     
  2. Francesco

    Francesco Member

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    My money is on the holders being the problem. If you can spring enough to get a newish Fidelity to compare I would not be surprised if that solves the problem.
     
  3. scootermm

    scootermm Subscriber

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    ironically francesco I just yesterday won an ebay auction for one fidelity 8x10 holder so will do some comparisons when I get that hopefully this week or next
     
  4. jon koss

    jon koss Subscriber

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    >>alright so Im having some issues with my ancient 8x10.
    >>Ive attached an image to show the problem....

    Hmmm... quite vexing no doubt.

    Three possible diagnostic tests:

    1. - Make identical exposures using the two different holders. If the defect changes location from holder to holder then it is likely the holders as Francesco has suggested. However, if the defect repeats identically despite switching holders, then I might look elsewhere. It would not be expected to see two holders (four sides) go bad in exactly the same way.

    2. - While you are waiting for your new holder you could try a quick and dirty test. You could take the lens out of the equation entirely and replace it with a pinhole. A largish pinhole would not be too troublesome to make and would allow you to rule out (or in) the lens as a factor.

    I had virtually the same lightstrike on my negs a few years back. I had tested the whole rig quite thoroughly with a wide angle lens in place and found zero problems. I then exposed my first "real negs" with a late model coated normal lens. Egads, disaster!! Switching back and forth from the wide to the normal confirmed that the problem was with the lens, despite its flawless appearance.

    3 - It would also be worth extending your discipline with the darkcloth to the area of the back/filmholders. If sealing the back off with your cloth solves the problem, then you know to look at how the holders seat, etc.

    Hope some of this helps. Good luck and let us know how it turns out.

    Jon
     
  5. Donald Miller

    Donald Miller Member

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    The one way of accurately determining the source of the leak is to remove the lens board from the camera. Insert a flashlight into the opening vacated by the lens board in a dark room. Then insert your holders individually checking for light leaks at the interface of holder and the camera back. Next pull the dark slides and check the light traps for light leakage. Wherever the leak is will show up this way. While your at it check your bellows. I have had bellows with pinholes that sure looked like holder problems.
     
  6. Mateo

    Mateo Subscriber

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    Another thing to try would be to remove the back from the camera, close the lens and stick your head in the camera with a darkcloth over you. It takes a while for your eyes to adjust but you will see any problem with the bellows or the lensboard.
     
  7. jimgalli

    jimgalli Subscriber

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    Go out in bright sunlight. Take lens out. Put eyeball in. Make sure holder is in place with fresh useable good film. Light will NEVER leak in unless there's film. Pull darkslide and voila. If that doesn't work try the same procedure from the other end.
     
  8. Deckled Edge

    Deckled Edge Member

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    Here's yet another thing to check. I had a very similar light leak to yours. I traced it to poor mounting of the Wide Field Ektar to the lens board. There was an edge leak which bounced off the bright rear element edge and made a linear swath 1/3rd into the image, vertically.
    PS: I have my best luck with old, wood 8x10 holders. I own about 20, and they work far better than the heavier, plastic/metal Fidelity holders. Certainly, a shot light trap is not unlikely after 80 years, but the Graphlex folks really knew how to make a holder, and all but the most abused have held up just fine.
    PPS:"Light will NEVER leak unless there's film." Jim, you crack me up!
     
  9. George Losse

    George Losse Member

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    Ok.... I looked at the attached scan and I don't see a light leak. What am I missing?

    I can see black on all the spots that hold down the negative so if there is a LL in the shot its not in the holder......

    Are we talking about the lighter area of the image that comes down through the shot? If that is the light leak, does it happen in the same place on all the shots or just with one lens on the camera (then it would be a lens problem) if it happens with different lenses then its a camera problem.
     
  10. scootermm

    scootermm Subscriber

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    thanks all for the advice. tomorrow morning Im going to do some testing. all the suggestions are helpful and hopefully Ill come to some conclusions.

    .... we'll see I guess.....
     
  11. scootermm

    scootermm Subscriber

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    okay
    bit of an update for anyone that is interested.
    I took the camera out on the back porch and had two shots loaded.

    shot 1
    loaded the film holder in. replaced the normal wollensak mounted lensboard with a brand new completely undrilled blank lensboard so as too eliminate any light coming in from the front.
    I pulled the darkslide and let the sheet of film "expose" to any light leaks for 20secs. I used 20 secs to over exagerate any light leaks to fully see their locations.
    returned the darkslide and pulled out the film holder.

    shot 2
    I then put my other film holder in and remounted my wollensak 12" lens. I covered up the entire camera with my focussing cloth. covered the bellows, the entire back standard and most of the front standard aside from the lens. I went under the focussing cloth and pulled the darkslide (all underneath the cloth) came out from underneath the focussing cloth. metered the scene and exposed the shot for 2 seconds per my light meter zone V reading.

    took both film holders into the darkroom and developed them in my standard manner. PMK Pyro 1:2:100 at 800 seconds. Fixed and washed them.

    the results:
    Shot 1 (no lens mounted) showed horrible light leaks at the top of the film holder region. where the darkslide is removed and reinserted.
    Shot 2 NO LIGHT LEAKS AT ALL. apparently covering everything up really made a huge difference.

    So I went back outside and put a unloaded film holder in the camera and removed the front lensboard and got down under the dark cloth and look into the front of the camera.... after about 3 mins under there my eyes had adjusted and there were horrible light leaks coming in where the film holders sits against the back standard/spring loaded part.
    Apparently there is no ridge for that part lengthwise notch on the film holders to rest on and the fabric that is working as a light seal isnt doing its job.
    My plan is to take the back down to the fabric store and find some fabric that will work as a light sealer and strip the present fabric off and replace it with some 3m spray adhesive and the new fabric. I will likely also get out the dremel and cut a notch into the back to facilitate the notch "locking" that the film holders have.

    any other suggestions anyone might have would be appreciated. and thanks again for the advice. the methodical testing seemes to help a great deal.
     
  12. Donald Miller

    Donald Miller Member

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    I am assuming that you mean the rib lock that camera backs have to allow the holder to be retained. If that is your problem then the remedy would appear to cut the necessary relief into your camera back.