Hello to everyone!
In a series of shots taken last year all came out just fine except for four consecutive shots, 2 identical exposures for each of 2 images. They show a broad stripe of blocked light (white in the negative, black in the print), 3 of the stripes being pitch-black across the top (of upright image), the first stripe however of similar width, but on the bottom end and not completely black but somehow like horizontally pleated.
I am not absolutely certain I can rule out a developing issue. But I think so, as these four negatives were developed in a batch of six in a MOD54 tank, the other 2 negatives being fine. All four shots were taken with a Schneider SA 5,6/90 and lots of rise (first image and backup 44 mm, second image and backup 46 mm). The lens allows for 47 mm in portrait mode, so that was quite close to the limit. F-stops were 33 2/3 in the first two shots, 22 1/2 in the two following shots.
I cannot swear if I had the Lee Wide Angle Lens Hood mounted, but I think I did so routinely, mounted with a wide angle adapter ring.
So, what possible mistakes would be capable of producing such phenomena?
If it was lens vignetting, caused by exceeding the image circle, shouldn't there be some round corner vignetting instead of a stripe? Also, I tried the same setup at home under well-lit conditions. Checking through the GG corners, I could not find any signs of vignetting at the apertures used. (Without rise no vignetting from f 11, with rise of 44-46 mm no vignetting from f 22.)
Second possibility, would a black stripe be consistent with blockage by the lens hood, wrongly adjusted? While checking the corners the Lee Wide Angle Lens Hood shows up only when fully extended (which I can rule out) or when in oblique position. The latter would have been possible. If I was in a hurry, e.g. because of fast approaching dark rain clouds, I might have inadvertently touched and turned the hood after having checked for vignetting. Or I might have had difficulties in checking due to light conditions.
I would love to pin down the cause. If I have simply exceeded the movement possible with this lens I would consider exchanging it for a SA 90 XL, although this would pose other problems with the TK 45s I used. At the occasion the four shots were the only ones I made with the SA 5,6/90. For all others I used the 72 XL, 110 XL, 150 and 240 lenses. This might be coincidence, but then it might not.
Image circle, lens hood or something else, what can cause broad black stripes?
Thanks,
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