Bronica SQ - vignetting or light leak ?

Discussion in 'Medium Format Cameras and Accessories' started by awaken77, Sep 6, 2008.

  1. awaken77

    awaken77 Member

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    I recently bought Bronica SQ set (including Zenzanon-S 80/2.8 , AE metering prism and 120 back).
    First roll revealed some problem - dark "stripes" along the edges of the frame.
    They can be seen on the exposed area of negative only, not in the spaces between.
    Since it was an expired film, it is possibly damage of the film itself.
    [​IMG]

    However, on the next film rolls, problem still exist, altough not so obvious.
    Here it is on the right side - looks like vignetting along the edge of the frame.
    [​IMG]

    Here it is less prominent, on the right side too.
    [​IMG]

    I thought it can be a light leak in the back, but light leaks usually appear like light stiripes, not darker ones, right?
     
  2. dances_w_clouds

    dances_w_clouds Subscriber

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    The light leaks appear darker because you know what light does to film. Vignetting would be circlular.;
     
  3. Q.G.

    Q.G. Inactive

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    Yep. The OP and i do.
    If it receives more light, for instance due to a light leak, the end result will be lighter. Not darker. :wink:

    Vignetting takes the shape of the thing that is causing the vignetting.
    Just like any shadow (which vignetting is) takes the shape (outline) of the thing that is casting the shadow.
    So it is only circular if the things that is causing it is circular. And there are other things that might cause vignetting that are not.


    Awaken7,

    It could be a processing thing (too much agitation).
    Or something inside the Bronica not moving out of the way properly.
     
  4. dances_w_clouds

    dances_w_clouds Subscriber

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    PARDON ME
     
  5. Andy K

    Andy K Member

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    How bright was the light where you loaded the film? Also are these scans of prints, negatives or transparencies? If there is a curve in film it can affect the scan of a neg or transparency.
     
  6. dances_w_clouds

    dances_w_clouds Subscriber

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    That makes sense film exposed to light gets lighter ????
     
  7. Q.G.

    Q.G. Inactive

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    :smile:

    Take a picture of something out in the open sun, casting a shadow, make sure the sun itself is also in the frame.
    Now what would you say would be light(est), what would be dark(est) in the picture? :wink:

    And/or take a look at the pictures the OP posted.
    See how, for instance, the shade below the sunflowers is darker than the nutated sunflowerheads, and ask yourself whether that really would be because the film receives more light coming from the shades. :wink:
     
  8. dances_w_clouds

    dances_w_clouds Subscriber

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    The truth rears its ugly head. If he had a camera where the shutter opened in the center the dark marks would be from a slow shutter with Not enough light getting to the edges. Even @ this late hr it makes sense. I don't know if any cameras have a shutter that splits up the center though. But we got off topic here sorry awaken77
     
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  9. Q.G.

    Q.G. Inactive

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    That's along the right lines, yes.
    A Hasselblad, for instance, has two baffle doors in the rear that flap out of the way. If they don't do that quick enough, or not completely, they shade the film.
    I don't know the Bronica well enough to know how it shields film against light when the shutter in the lens is open. But whatever it uses not opening fast enough (or not completely) could cause this.
    The fact that it gets better after some exercise might indeed point in the direction of a mechanical problem: gummed up lubricants, getting better when used again.

    A central shutter (a.k.a. leaf shutter) in the lens (which this Bronica has) also opens from the center, but will not vignet in the same way. Not even when it doesn't open completely. Due to its position, it simply acts like an aperture, and not opening completely would lead to an evenly less exposed image.
    So that would not be it.
     
  10. awaken77

    awaken77 Member

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    I thought about that (slow mirror movement). but... I always use mirror lock-up feature on Bronica, so this is not an issue.

    as for light leaks - they look dark on the negative, but light on the positive.
    here is what I got on my Iskra, typical leak in the camera body
    [​IMG]
     
  11. benjiboy

    benjiboy Subscriber

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    If I had this problem, before I did anything drastic, I'd shoot a fresh in date roll of film ,and get it processed at another lab.
     
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  12. glbeas

    glbeas Member

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    I agree with Benjiboy. From what I know of SQ cameras theres not anything to make a vignette in that orientation. It looks more like a processing issue. It may have been the result of problems the lab was having getting decent prints from the old film.
     
  13. MikeSeb

    MikeSeb Member

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    I vote for a processing or scanning issue. It's too even and regular to be a light leak at the edge of the film, such as you'd see from a not-tightly-enough-wound film spool; those are more irregular.

    You can also see this with certain film scanners along the edges of the film; i've never understood if fully but it has something to do with the way the light source is reflected back or otherwise distorted. Especially visible when there are large expanses of even, lighter tone such as sky.
     
  14. KPT

    KPT Member

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    I had the same issue once with a roll of 120. My issue was that i put the roll upside down in the tank and that caused the reel to be 1/4 above the developer and gave my that dark band through the entire roll.
     

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  15. DWThomas

    DWThomas Subscriber

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    As an SQ-A owner, I concur with benjiboy, glbeas and MikeSeb. The mirror/light baffle travels vertically, so unless you took these shots with the camera laying on its side, that couldn't produce that shadow. Light leaks produce lighter areas, not darker, in the final positive image.

    DaveT
     
  16. Andy K

    Andy K Member

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    I did the same thing with the second roll through my SQAi. I was mighty pee'd off at myself because I got some really nice fog shots on that roll: http://img.photobucket.com/albums/v223/Minitar1/MonochromeFilm/ContactSheetPierR2-1.jpg
     
  17. MattKing

    MattKing Subscriber

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    You aren't, by any chance, using a lens shade are you?

    If so, is it the right one?

    Matt
     
  18. awaken77

    awaken77 Member

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    I use standard square lens shade which came with the lens.
    but I don't put it on most of the time, so there isn't a difference between the shots with/or without shade

    I have one roll of Delta 400 undeveloped, and if this roll will not have the same defect - it's a lab issue
     
  19. evilhomer78

    evilhomer78 Member

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    I would take the back and the lens off of the body and flip the mirror lock up then look through the body. There may be something protruding from the side of the body. In my sq-a there is foam lining the body. Its a possibility some of the foam is coming unstuck in your camera. Also Look at the back without the insert or dark slide in to see if there is something where the dark slide goes. I had a back that had some paper wedged in there from a previous owner, how it got there I have no idea.
     
  20. panastasia

    panastasia Member

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    A roll taken from the freezer and exposed before it is allowed to reach ambient temperature will look very similar after it is developed (this happened to me and it didn't seem to be a condensation problem). I would guess that the other extreme would do the same - exposure during excessive high temperature conditions. The problem is with the temperature differential, or gradient, across the film. This is my best guess.
     
  21. awaken77

    awaken77 Member

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    I developed Delta 400 myself - no such artefacts:
    [​IMG]
    ***
    [​IMG]
    ****
    it seems a lab processing issue. unfortunately I cannot change lab, becouse there is only one in our city, capable to develop C-41 MF film
     
  22. Q.G.

    Q.G. Inactive

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    Just tell your lab what's happened, show them their and your results if necessary, and ask them to not do this again.
    It's in their interest too not to screw up their customer's film.
     
  23. John Koehrer

    John Koehrer Subscriber

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    C-41 kits aren't especially difficult to use. Shouldn't need more than you have for B&W.