Red Pixel

[oceantan]

I was testing the noise level in my 10D at the various ISO levels.

I noticed at ISO 800, there was 1 red pixel. And when I went up to ISO 1600, the same red pixel was there and with an additional 3 or 4 red pixels throughout the frame. ISO100, 200, and 400 were red pixel free (even with magnification).

The red pixel that was noticeable at both ISOs could be seen when played back on the camera without magnification. The others at ISO1600 can only be seen if magnified.

Is this acceptable? Should I send it back to Canon?

[redbutt]

The manual for the 10D mentions something about the LCD possibly showing artifacts that do not make it to the final image. Have you put the images into Photoshop and still see the red pixel?

[oceantan]

I put up the images in PS as mentioned and the dots are still there. Quite obvious when I zoom in 100%. Like stars in a night sky.

Anyhow, I have taken soccer shots at ISO 1600 and could not see these dots.

I guess they must be artifacts. But I do not recall seeing them in my D60..

I will be bringing it in to Canon tomorrow and see what they say.

[bluebomberx]

They are hot pixels - I suppose Canon would call them artifacts. I have one hot pixel in my 10D at ISO 400+. I had an image printed 11x14 and the hot pixel does not show. One pixel isn't going to show up in a print.

-Richie

[Carbon]

I've noticed that the exposure time seems to affect the hot pixel appearances.

I tested by shooting with the lens cap on, manual focus, max resolution and highest quality JPEG compression.

At ISO-100, I can't get any pixels to show, even with a 30 second exposure.

However, at ISO-400, with a 30 second exposure, I can see at least 12 pixels of various colors.

ISO-400, 20 second exposure, still a bunch of dots.

ISO-400, 6 seconds exposure, there's only 1 dot.

This is at warm ambient temperatures, around 80 degrees. Camera was off for hours before shooting.

What are you guys getting?

[Guillermo Freige]

This is normal. Al CCD and CMOS cameras have those colored pixels in long exposures. A very intresting article about noise and digital cameras can be found here:

http://www.outbackphoto.com/dp_essentials/dp_essentials_04/essay.html

As far as I know, the colored pixels are caused by the "leakage current" (explained in the article)

[Carbon]

Thanks for the link! Interesting article...