I need some advice on an irritating problem regarding my exposed film. For the second consecutive time I received a batch of slides back from the lab with dark, unexposed areas on the top and bottom of *some* of the slides. To see an example, go to http://www.photo.net/photodb/photo?photo_id=3295174. I am at a loss to explain the source of this problem and I'm hoping someone might be able to offer some insights.

This problem only occurs with images taken with the Schneider 110 XL - not my 75mm or 240mm lenses. It also seems to occur mostly, but not exclusively, on vertical images. The dark areas are always on the very top and bottom - never on the sides - and appear at different places on different images. The dark areas do not show up on the ground glass, at least not when the lens is wide open. There is nothing in front of the lens (e.g., part of the darkcloth, my hand, cable release) that would seem to account for these areas. The shape of the dark areas is inconsistent with the effects of exceeding the lens image circle, and given the huge image circle of the Schneider 110 XL an image circle explanation seems very unlikely. I've been using the same equipment for the past year (including a newer Ebony 45S), as well as the same lab, and this problem developed only recently.

I'd appreciate any ideas about what might be causing this problem and what to do about it. Thanks!