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Old Jan 13, 2010, 8:13 PM   #1
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Default Picture looks oblique?

Hi, I have Sony Cyber-shot DSC-W220 and am not sure if this is a lens problem.

Can you guys take a look at it?

I took that in flat surface, specifically in LCD and the one with a spoon .. well you can guess it.

kind of bit bothering why it looks oblique or it was pinched or something.. am not using any aperture (am not sure how you guys call that extra lens attached on your SLR or DLSR)
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Old Jan 13, 2010, 8:41 PM   #2
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I see two flaws in the images you posted:
  1. Vignetting - The edges, and especially the corners, are significantly dimmer than the center. See http://en.wikipedia.org/wiki/Vignetting
  2. Barrel Distortion - The image projected by the lens is not rectilinear. That is, straight lines bow in the corners. See http://en.wikipedia.org/wiki/Barrel_distortion
These kinds of things happen in compact digicams at their shortest focal lengths (widest angles of view.) In well lit scenes with no horizontal or vertical straight lines near the edges, these flaws aren't noticaeable. Your images are specifically intended to show those flaws, and were quite successful.
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Old Jan 13, 2010, 8:48 PM   #3
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I see two flaws in the images you posted:
  1. Vignetting - The edges, and especially the corners, are significantly dimmer than the center. See http://en.wikipedia.org/wiki/Vignetting
  2. Barrel Distortion - The image projected by the lens is not rectilinear. That is, straight lines bow in the corners. See http://en.wikipedia.org/wiki/Barrel_distortion
These kinds of things happen in compact digicams at their shortest focal lengths (widest angles of view.) In well lit scenes with no horizontal or vertical straight lines near the edges, these flaws aren't noticaeable. Your images are specifically intended to show those flaws, and were quite successful.
what about the one with the spoon? I edited this picture and added the red lines to make the "Barrel Distortion" more noticeable.

And do you also mean my new DSC-W220 have to go back to where I bought it?
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Old Jan 13, 2010, 8:53 PM   #4
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Quote:
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And do you also mean my new DSC-W220 have to go back to where I bought it?
na, this happens with all digicams.

in most normal photographic instances, it would not be so noticeable to be a bother. for those instance where it is, you can help out the barrel distortion in post-processing.

nothing to worry about, everything is working as specified.
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Old Jan 13, 2010, 8:55 PM   #5
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what about the one with the spoon? I edited this picture and added the red lines to make the "Barrel Distortion" more noticeable.
Yes, I saw that, and that's also barrel distortion.

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And do you also mean my new DSC-W220 have to go back to where I bought it?
It's a design flaw, not a sample defect. Any other W220 will have the same flaw. If it interferes with the types of photos you want to take, you should exchange it for a different model or brand.
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Old Jan 13, 2010, 9:00 PM   #6
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thank you so much! @Hards80 and @TCav
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Old Jan 13, 2010, 9:13 PM   #7
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also, the distortion goes away as you zoom in. so if you need straighter lines (and for some reason don't want to do in post-processing), just zoom in a step or 2, that will resolve most of that problems.
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Old Jan 13, 2010, 9:15 PM   #8
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also, the distortion goes away as you zoom in. so if you need straighter lines (and for some reason don't want to do in post-processing), just zoom in a step or 2, that will resolve most of that problems.
it is! how'd you found that out?
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Old Jan 14, 2010, 5:11 AM   #9
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This issue isn't limited to digicams. Even many DSLR lenses exhibit this behaviour. As was mentioned, this can be mostly corrected with software. The other common problem a lens can display is pincushion, in which the straight lines seem to bow in from all edges, and usually shows up at the tele end of the lens.
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Old Jan 14, 2010, 7:03 AM   #10
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Flaws in a lens are most apparent at the extraemes of its range. What you've been doing is testing your lens at it's widest angle of view and seeing those flaws. As you move away from that extreme, I have no doubt that the flaws will diminish. But when you start to critically examine the results you get at the longer focal lengths, other flaws will appear.

This happens with P&S digicams because they try to do everything with the only lens they have. And, as rjseeney has said, dSLRs have similar flaws, albeit to a lesser degree and a greater cost. There are no perfect cameras (despite the best efforts of companies like Leica and Hasselblad); you need to pick the compromise you can live with right now, as your requirements, tastes and sensitivities are certain to change over time.
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