Hot Pixels

[KevinStecyk]

I am posting this message on behalf of a Flickr friend who is encountering difficulty with his new camera.

I got a Canon Rebel T1i (500D) earlier this month (October 2009), and found it the sensors picked multiple red dots, when I had a long exposure, with the lens cap on (or just a dark background). I brought it in, and the store (Future Shop in Calgary) replaced it under my Extended Warranty. But, now, I have a single purple dot. I'm wondering how common is this type of problem? It doesn't appear with shorter exposure times used in daytime photography. So, is this something I should accept or protest about. Two in a row seems bad. But, it's something I think most people wouldn't notice.

He's made another camera exchange. Is this problem something that should be expected?

[ChuckWestfall]

Exchanging the camera isn't going to resolve this issue.

All digital cameras develop hot pixels over time. It's the nature of the technology. But trying to detect them via long exposures with dark frames is basically a "torture test" that often has absolutely nothing to do with the results one can achieve with accurately exposed images taken at shutter speeds less than 30 seconds.

If you can still see the hot pixels in well exposed images or video clips, it might be worthwhile to send the camera in for adjustment. The Factory Service Centers have diagnostic equipment that can "remap" hot pixels to make them disappear. But there is no such thing as a permanent solution, because the hot pixels can be caused by a variety of issues including the penetration of the camera by cosmic rays in the atmosphere.

[KevinStecyk]

Hi Chuck,

Thank you for your very thorough and helpful response. I will pass your answer to my Flickr friend.

Sincerely,
Kevin