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Old Jan 18, 2011, 12:38 PM
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Dance the skies...
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United States, MA, Walpole
Joined Dec 2003
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Originally Posted by wayback View Post
There was a post a while back that mentioned an anti-vignetting filter or plugin for VirtualDub, or maybe it was for AviDemux. Has anyone tried anything like that?

I guess the vignetting, or flashlight effect, or whatever, is really noticeable to me in the videos posted here. I remember that someone tried enlarging the opening in the case, and it made no difference. So it comes down to the lens/sensor combination they chose that causes the problem. Well, maybe that's something they would consider changing. In the meantime, I just wonder whether a software filter might help.
The filter is for Vdub. It is something I want to try when I get a chance, but you first have to re-encode the video into .AVI format before you can import into Vdub (at least on W7 PCs), so it's a double editing task even if it works. And it takes some additional work to first do a recording of a white background to make a mask that matches your camera exactly. If it works, it might be worthwhile for some, but not without some extra effort. If it just brings the corners and left/right edges of the frame into equal brightness, that may not improve things that much, because the darkened extremes of the frame also has different color saturation and white balance. The HD camera does not maintain consistent color saturation and white balance as the scene brightness changes. The video I've shot with overcast skies has good color saturation, but in bright sunny skies the color is considerably over-saturated. It just something we have to accept with a $40 HD camera for now. The old 808s do the same thing, but since the CMOS output is 4:3 aspect ratio instead of 16:9, it's easier for the similar size lens to illuminate its CMOS array more evenly, so vignetting is not as great.

AviDemux has the ability to import third party filters... maybe it's possible to use the Vdub filer in AviDemux.

I plan to investigate all this when I have some spare time. Also, the need for a better lens was also passed on to the vendors for consideration. They said finding one to fit the small (6mm?) threaded boss of the CMOS module was the problem. A better lens might exist that will fit... just need to find some sources for a possible fit. I've done a little web searching, but haven't come up with anything.
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