Bronica GS-1 Light Leak

Discussion in 'Medium Format' started by jeff_adler, Sep 9, 2014.

  1. I shot a test roll of XP-2 Plus on Sunday with a new (to me) Bronica GS-1. The lens was one of my 100/3.5s, the back was one with a 220 6X7 insert which I removed and replaced with a 120 6X7 insert. The prints from all ten frames show a light leak near the lower left hand corner. In nine of the frames the affected area is small. In one it is larger. The affected area in each frame does not extend to the edge of the negative. The spacing between the frames is not perfectly even but it is never too wide or too narrow. When I look inside the back I see that there is no felt or foam sealing material. There is just a series of baffles. The only cause for the light leak I can think of is the space left when the dark slide is pulled out. Based on the angle of the sun in the shot with the more severe light leak I think the sun must have been shining right through that slit. I suppose the obvious test is to shoot another roll but with black tape covering the slit from the time the back is attached to the time the roll is fully wound through. Does this sound right?
  2. Actually, that sounds like what seems to happen with my RB67 when there is a strong sidelight. My leak shows itself primarily in the space between frames.
    It can't be coming from the felt/foam seals, since I replaced them some time ago. Since it hasn't really adversely affected the images, I haven't "done" anything about it, but now I think I will carry a small amount of black Gorilla Tape in the bag - wouldn't hurt to tape up the darkslide slot, I don't think.
    I'll be interested to read other users' posts about this.
  3. Only spent a weekend with a GS-1 but recall that the back was very similar to the SQ-B's I later bought. There's likely a thin strip of seal material at the hinge of the outer shell that holds the insert. I'm guessing that's the problem. It's an easy DIY fix with some adhesive-backed foam from a craft store. There's nothing between the back and the body to leak, though you can try some tape on the dark slide slot to rule that out.
  4. On the GS-1, when not careful or when working in a hurry it is actually possible to clamp the back with one of the hooks misplaced. Happened to me once and all the shots were fogged. But you would have seen it when you took the back off, for it is harder to unhook. The camera is lightweight for a 6x7 format. If not exactly built like a tank, it's nevertheless a robust camera.

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