Dead Pixels on a 30d

Sean Kirk , Aug 14, 2006; 11:59 a.m.

I know that sometimes with LCD's and monitors, pixels can just die, is that possible for DSLR sensors? I've noticed with some of the bulb shots of the sky that there are a few scattered pixels that are just solid red and blue. Its not my monitor becuase if i move the photo around on the screen they're still in the same spot on the photo. I took a bulb shot with the lens cap on to see the results and there are a few that consistantly keep showing up, my guess is that the pixels on the sensor are dead since these same spots are in a few pictures? Or is it noise? Any thoughts, experiences, ideas, suggestions?

Attached in the bulb shot.

Attachment: IMG_2222.JPG

Responses

Rob Bernhard , Aug 14, 2006; 12:08 p.m.

Don't confuse dead pixels with hot ones. Hot pixels show up with long exposures. The 30D has a dark-frame subtraction mode (aka: noise reduction) which will subtract them out for exposures longer than 1 second. You'll find more information in your user manual.

Mars C , Aug 14, 2006; 12:15 p.m.

Thats normal, I have that too, just use the NR. I think its on custom function.

Sean Kirk , Aug 14, 2006; 12:49 p.m.

Interesting, I've never heard of hot pixels, thanks for the heads up. I had the custom function noise reduction setting on in all of the pictures that they have been showing up, I have it set to AUTO, so it does it when the camera thinks it needs to, but the camera definitly preformed the noise reduction even on the ones where the same pixels showed up.

Chris Kolaczan , Aug 14, 2006; 12:53 p.m.

this is a dead pixel (as far as I know)

Attachment: dead.jpg

Derek Hammond , Aug 14, 2006; 02:32 p.m.

To the best of my knowledge all camera sensors have dead pixels - they are usally mapped out in the camera firmware during manufacture. If they are causing you real problems then a visit to a canon service centre should result in the firmware being adjusted to map them out.

Mars C , Aug 14, 2006; 06:44 p.m.

Mine does'nt show up on short exposure even with out NR. it only shows up on 10sec. and above exp. w/out NR.

Maybe we have different problem.

Gordon Kraeger , Sep 15, 2006; 08:03 a.m.

May I join this, as last night I did my first Bulb expo and in the black area is a white dot. It's the same place in all three exposures and in a lens-cap-on exposure. I had heard that "hot" pixels showed color. If the firm ware maps it, what does it do with it, since it shows up in the finished exposure? How does one handle this; get used to it, send it in for repair, or how?

Rob Bernhard , Sep 15, 2006; 09:06 a.m.

<<How does one handle this>>

You read the manual on how to turn on Noise Reduction.

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