 Marquee Smith |
What causes the dark edges Please look at these two pictures and please explain to me why I have the circular shadows at the edge of the picture. Any suggestions on how to avoid it in the future. The photo was taken in my dining room against a white wall, using the Canon 580ex speedlite. One photo used the flash at a 90 degree angle the other at 45 degrees. Camera was set on Program mode. Thank you in advance for your imput and advice. Marquee
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Marquee Smith |
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Marquee Smith |
OK, I can't upload the pictures from work. They are the first two photos in my gallery. Sorry for all the confusion.
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Jon Close |
Found them in your gallery. A couple of possible causes... (1) Flash coverage narrower than the lens's field of view. I don't think that's the case in these examples since you used indirect bounce flash. (2) Many lenses exhibit light fall off in the corners, especially at their widest aperture setting. Usually cured by using smaller apertures or better designed/quality lenses. (3) Also called vignetting, it can also be caused by an inappropriately sized lens hood or filters - especially when more than one filter is stacked. The extended filter rings or the hood block the lens's view at the corners.
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Marquee Smith |
Thank you Jon, I think reason #2 may be correct. Program mode uses a wide aperture. I think it was at 5.6 in these photos. I did not use a lens hood and I don't stack filters. Jon, for future reference... If I used a smaller aperture to avoid the fall off and was shooting against a colorful or textured background, how would I then create the DOF usually achieved with a larger aperture?
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Jon Close |
For less DoF at smaller apertures - decrease distance between the camera and the subject (ie. get closer), and/or increase the distance between the subject and the background (move away from a wall, backdrop, etc.).
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Jon Close |
P.S. Just curious, what lens were you using? If a zoom, what focal length? You did not stack filters, but did you have a protective filter on? With some lenses even a single standard filter will cause vignetting one should instead use the thinner wide-angle filters, or larger diameters with step-up rings.
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Marquee Smith |
I was using a Sigma 70-300mm set at 135 or 200, I don't remember. I do keep a UV filter in the lens. If I take it off would that lessen the vignetting? What is a step-up ring?
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Jon Close |
A step-up ring is a simple adapter with male filter threads sized for the lens on one side (say 58mm), and female threads of a larger diameter (say 67mm) on the other side. It allows one to use larger filters on a lens to avoid vignetting problems, and/or so that you can use one set of filters on several lenses that have differ filter diameters. I would not expect that lens to vignette due to any filters, at least at any zoom setting longer than 70mm. You can try a test without the filter, but I think you're earlier post attributing it to (2) is correct. Re - eliminating vignetting by shooting at a smaller aperture - Another solution is to simply crop vignetting from a portrait like this since that area is just "dead space" anyway.
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Marquee Smith |
Jon, Thank you for all of your help and info.
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