Uneven light fall-out on transparencies

[QT Luong]

On two of my recent trips, I've noticed that some 5x7 transparencies have a kind on light fall-out on the edge. The area which is affected is always the right edge, and the light fall-out takes the form of a darker band which is approximatively vertical and about 0.5 inch (1.5cm) thick, between 1 and 2 stops. The left edge is OK, and no swing was used. The problem occurs only when using a Schneider 110XL with exposures of a fracti on of a second in strong daylight (longer exposures seem OK). No lens shade was used, and I have checked for vignetting through the corners of the ground glass. Film was processed professionally. Because I have not observed the problem with longer exposures and other lenses, I suspect the shutter (prontor professional) but I don't know how to test this ide a as it appears OK. Thanks for any suggestions.

[Sorin Varzaru]

I suspect you stepped down when you took those shots. That means the shutter must malfunction significatly to create that kind of effect. You should be able to see it with the naked eye.

[Cesar Barreto]

Mr. Luong, Maybe, you could trigger this lens on a flash and photograph the shutter right open, checking if there's something on the way. Good luck!

[Wayne_6692]

I cannot imagine a defect that might occur with a leaf shutter that would manifest itself in a linear band. Since the image is reversed on the film it would help to know which "right edge" you are speaking about.

[M.]

Damn, Q. I have the same trouble with 35mm trannies, and thought it was from an uneven focal plane shutter. Could it be from Polarized light?

[Matt_1193]

Q.-Tuan,

Where do you get your 5x7 films. I am having a hard time finding any lately.

[N Dhananjay]

Don't know if this is the same thing but I experienced something similar to what you mention. I was shooting B&W and would get negatives with lower density along one of the 4" edges of the film. This seems to correspond to what you are describing i.e., darker edge with transparency film. My first notion was light leak but then I realized fogging would increase density, not reduce it. It took a long time to figure it out. It was a light leak which was coming out the side of the bellows close to the film plane. The frame blocked this fogging light from hitting the 4" edge closest to the hole but the light sort of sprayed across the rest of te neg, increasing density theree. Of course, when I viewed the neg, it looked the correctly exposed part (i.e., the bit that was not hit by the light leak) was underexposed compared to the rest of the film that was. Proof that perceptual illusions and bugaboos afflict us way after the picture is taken...

You mention that you only get this with one lens, which seems to rule against a bellows leak (althought it might be worth checking for that too - pinholes reveal themselves and hide themselves in the field depending on the focal length used since you rack the bellows out or fold them in etc). Since this is a shorth focal length, is it possible that there is a light leak in the bellows near the lensboard which doesn't affect the film much when the bellows is racked out with a longer focal length but is visible to the film with shorter lenses?

Good luck. Hope you isolate the gremlin and toss it into outer darkness where it belongs... Cheers, DJ.

[N Dhananjay]

Sorry, forgot to add - the strong daylight also makes me suspect pinhole i.e., it may be the beginning of a pinhole and it take strong light to get through in sufficient amounts to affect the film. Although I'm lost as to why longer exposures are unaffected. Cheers, DJ.

[Glenn Kroeger]

Since nothing in the plane of the shutter/iris can be imaged in the film, I cannot see how that could be the source.

With the problem restricted to one lens, it would seem like the problem involves either the lensboard, or the relative postion of the front and rear standards causing a light leak.

[john g]

Check your lens board to see if it sits properly. I had the same problem with a warped board. Maybe try switching lens boards.