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Old Apr 30, 2010, 9:44 PM   #1
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Default What are types of lens distortion a camera can have?

I'm curious what kind of lens distortion a camera could have. I know the barrel distortion, where the corners of a lens make the image look "bent".

There is also a specific one I'm looking for. Is there one that can cause the top left corner to be much softer than the rest of the picture? I have a S1800, and the entire top left corner (or the entire 2nd quadrant in the Cartesian plane) is very visibly softer than the rest of the image. It gets progressively worse as you itch closer to the leftmost and topmost part of the image.

What kinds of distortion should I look out for in cameras?
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Old Apr 30, 2010, 9:49 PM   #2
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That sounds like a problem that should be covered by the manufacturers warranty. Can you post an example of what you're getting?
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Old Apr 30, 2010, 9:56 PM   #3
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sample image
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Old Apr 30, 2010, 10:17 PM   #4
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That certainly doesn't look good, but try something else. Tape a full sheet of newspaper (2 facing pages) on a wall. Place the camera even with the center of the page and zoom so the newpaper fills the image. The photo you provided was shot at 1/17 second, which is too long to be shot handheld, so make sure the camera is on a tripod or some other steady surface. (Tape the newspaper so that it would at the appropriate height for the camera to be on a tabletop, for instance.) Then post that image.
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Old Apr 30, 2010, 10:18 PM   #5
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That picture was taken on a table (so zero hand shake).

I'll try the newspaper idea now.
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Old Apr 30, 2010, 10:35 PM   #6
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image 1

image 2

Of course the camera was on a table, not in my hands. The only thing that can possibly affect this is floor vibration, which I don't think I have any.
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Old Apr 30, 2010, 10:43 PM   #7
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It helps to have your subject be completely flat, and the camera perfectly square (or as close as you can get to perfectly square) to the subject - reason for TCav's suggestion of the newspaper taped to a wall. A good subject is the classifieds, lots of small text to judge and no photographs. If the camera is at an angle what could appear to be a problem might really be one part being out of focus because of the different distance. While I think your sample is very suspect, I wouldn't call it completely conclusive.

I'm not at all familiar with the design of your camera, with dSLR lenses you can have one element of a lens get knocked out of alignment, causing problems like what you described.
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Old Apr 30, 2010, 10:55 PM   #8
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Here is a picture of cinema times, which has a full panel of small text.

small text

My Fuji S1800 is a superzoom camera, not a DSLR. It only has 1 len.
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Old Apr 30, 2010, 11:19 PM   #9
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Without a doubt, the left edge of the images is less sharp than the right edge. If you just recently purchased htis camera you should be able to return it, if not for a refund, at least for a replacement. If that time has come and gone, you should be able to return it for warranty work.
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Old May 1, 2010, 12:45 AM   #10
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Definitely not normal. Send it into repair. It looks like some element in the lens is out of alignment.
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