 Murray G. A |
Eliminating black coners of photos After buying a 2nd hand Pentax SFX I ran 2 rolls of film through it - Konica ASA 100 and Fuji ASA 400. The majority of photos were taken on overcast days. Two issues have cropped up. 1) On both films (although the 2nd Fuji the issue was not as numerous) some of the photos had black 'rounding' in the corners (usually the rt-hand side) as if somehow on that side the curvature of the inside of the lens barrel was intruding in the photo. 2)With shutter speeds selected automatically by the camera, the Fuji film has come out noticeably darker and colours less intense than the Konica (which was, for most (but not all) photos darker than I would have liked), although both times the camera correctly identified the film speed and should have adjusted accordingly. Should next time I tell the camera that the film is of a slower speed to convince it to take slower shutter speeds? I bough this camera so I had a film camera that could work competantly on auto to complement my fully manual one, so would prefer it if it was possible to keep the fully auto features. I am guessing that it may be a camera fault as with the same Fuji ASA400 films I have taken fantastic photos with a Minolta X-300 and my wife has with a Minolta Dynax 300. Thanks
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Debby A. Tabb |
It would be nice if you could post that example here. But let me ask you this,were you using a lens hood during this shoot? sounds simple but I see it all the time.
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Alan N. Marcus |
Hi Murray, In this post I will address only the black corners. A camera lens projects a circular image that is much larger than the frame mask. The mask I am taking about is the black rectangle, at the rear of camera, it is a baffle that molds the frame dimensions. All lenses produce an image that has reduced light energy at he edges, this corner darkening is called a vignette. On slide film the vignette effect is lighter edges at the corners. Generally a vignette is not noticeable except when shooting using tremendously wide angle lenses. Furthermore, when observed the vignette is seen at all four corners. So, what would cause a vignette on just one side? More marginal technical gobbledygook from-
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Alan N. Marcus |
Some points clarified from above: When a camera lens vignettes the edges of the image display reduced light energy. Negative films reveal this vignette with reduced density at the edges (four corners) of the film. Prints made from negative films, both color and black & white have darker edges. A well designed photofinishing projection printer somewhat counters the camera’s vignette when negatives are printed on conventional printing papers. Slide film displays a vignette dark at the edges and in severe cases the corners appear somewhat rounded. Prints made from slides are more likely to show a vignette; both the printer lens and the camera lens compound the problem and maybe the printer lamphouse will be a contributor.
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Murray G. A |
Looking at the photos again, of the ones with the black corners a few also have the same thing on the left (but nowhere near as pronounced or intrusive as the right. I've attached a photo of one of the photos taken (sorry, ny scanner does not want to work at the moment) so you can see the exact effect. To answer a previous question, yes I was using a 49mm lens hood that came with the camera. Thanks
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Murray G. A |
Looking at the photos again, of the ones with the black corners a few also have the same thing on the left (but nowhere near as pronounced or intrusive as the right. I've attached a photo of one of the photos taken (sorry, ny scanner does not want to work at the moment) so you can see the exact effect. To answer a previous question, yes I was using a 49mm lens hood that came with the camera. Thanks
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