The Sleeping Giant's Sea Lion

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I have these tiny dots in a lot of my pictures. They look like tiny stars.

On this Nikon D60 I've tried cleaning the area where the shutter is (what's this called?) with a hand pumping duster, but they're still there. I can't see a single speck of dust.

Does it look like a stuck/dead pixel problem?

I am about to list this camera for sale and want to disclose the issue properly (unless you can help me remedy it).

Thanks!enter image description here

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1 Answer 1

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Those do indeed look like stuck pixels, however I'm curious if they are always in the same place? A stuck pixel is always there, in the exact same spot, regardless of other picture detail. I would try taking a black exposure with the lens cap on, and see if any of those pixels light up. If none do over several exposures, then it might be some kind of bayer interpolation issue. If those specific pixels always show up in a black exposure, they they are indeed stuck pixels. Most modern DSLR cameras have a feature or the ability (it may be buried) to map and exclude stuck pixels from interpolation. Generally speaking, ignoring the pixel is better than including it in interpolation. I am not aware of any way to actually "unstick" a stuck pixel, and I have heard that sensors ship with pre-mapped stuck pixels every so often.

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I see them with the lens cap on. Shipping sensors with pre-mapped stuck pixels? That sounds pretty shady. Thanks for the tip. I'll see what I can find. –  Louis May 30 '11 at 4:28
    
well they sell monitors with dead pixels too... –  Dr.Elch May 30 '11 at 4:37
    
you'd never know if they were shipped with a few pixels stuck and premapped. The data for that pixel will then be computed based on surrounding pixels. It's a rare day indeed when you'd notice the difference. For that reason (and the same for screens) there's a set (LOW) number of stuck pixels that's considered acceptable for shipping (and warranty usually doesn't cover a number lower than that either for servicing or replacement). –  jwenting May 30 '11 at 4:59
    
Ask yourself: if you'd not been looking at that image through a microscope (essentially), would you ever have noticed? The answer should be no, which is why a tiny number is no problem (you probably only noticed because they were close together). Sensors are expensive enough to make, if they were scrapped from the line for 1-2 dead pixels, they'd cost even more (dropping failure rate on production lines is the only reason sensors get cheaper any more, they're pretty low margin items despite the high price). –  jwenting May 30 '11 at 5:02
    
Good point, I guess a low number of problematic pixels is acceptable. But they are easily noticed in certain situations without zooming, usually ISO 800 and above. At ISO 400 and below there are just a few, but at 800 and up they really come out. The lens cap test looks like a picture of the galaxy, near stars, red-shifted stars. I was having a bit of fun exploring it actually. –  Louis May 30 '11 at 5:28

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