How many not pixels in 6 month old camera body = warranty repair?

[conropl]

Have you tried the "secret" dead-pixel remapping feature? Every time you do a manual sensor clean (even if you don't actually clean the sensor) the DSLR will check for new dead pixels and update the secret list of dead pixels, so they can be interpolated out of the raw data before it is written to a file. To make the remap even more effective, run the camera in live view for a few minutes (or longer) to get the temperature of the sensor up.

So... heating up the sensor just melts away the dead pixels

But I do have a question: I realize that long exposures heat up the sensor and can cause damage. So I limit the real long exposures (10-50 minutes) to cold nights (usually below freezing or very close to it) to try and mitigate some of the damage to pixels and that is usually when the night sky is clear anyway. So is the cold atmospheric conditions enough to prevent the sensor from heating up and damaging the sensor?

[Daniel Browning]

So... heating up the sensor just melts away the dead pixels

The way it works is that dead pixels tend to be strongly correlated with Time value (exposure duration) and Temperature. The longer the exposure and the greater the temperature, the more dead pixels there are. Temperature doesn't usually become a factor in until the exposure gets longer than 1/5 second or so. Canon doesn't let you adjust the time value of their dead pixel remapper, but at least you can control the temperature.

But I do have a question: I realize that long exposures heat up the sensor and can cause damage.

I don't think it can cause damage. At least, I've never heard of it being a problem. The cold weather does reduce thermal noise ("dark current") though, so it is definitely helpful for those 10 to 50 minute exposures. An alternative method is to just take many short frames and add all the frames together in the computer.

[Busted Knuckles]

Tried it - nope still a white dot in all frames - full size still is is often lost in the clutter for reproducing a "snap shot"... ummm not what I bought a DSLR for.... and Video... oooffff.... big white dot just lower/left of center ummm usually within the subject matter neighborhood.

[conropl]

An alternative method is to just take many short frames and add all the frames together in the computer.

I do not have the software to do that yet, but it is my plans.

[neuroanatomist]

Have you tried the "secret" dead-pixel remapping feature?

Daniel, how do you expect Canon to keep this a secret if you go blabbing it all over the Interweb?!?

[Kayaker72]

Daniel, how do you expect Canon to keep this a secret if you go blabbing it all over the Interweb?!?

Ha ....Well, he shoots Nikon now, I guess keeping Canon's secrets is no longer that important. Great for those shooters like me.

[Kayaker72]

Extremely cool. Thanks Daniel. I just performed your "secret" dead-pixel remapping feature. Most red dead/hot pixels were gone after one time. For the larger blue dead/hot pixels, it took 6 times. But they are gone.

Thanks for the tip.

[Daniel Browning]

You're welcome. Glad it worked for you.

[Dr Croubie]

I tried that 'sensor cleaning' pixel remapping numerous times on my 7D when I first got the dead pixels, before I sent it to be repaired. Maybe it worked for one or two of them I didn't notice, but the rest were stuck there, and didn't move (even after sometimes 15 minutes of 'cleaning').
Another feature the K-5 has over the 7D, there's a menu-option for 'pixel mapping' in there. (come to think of it, there's a 'pixel mapping' option in my 5 year old Olympus 8MP P&S compact thing). Again, canon, why not you too?

I always wondered how I got so many dead pixels, and seeing as it's out of warranty, I can wonder aloud if it had anything to do with that solar eclipse in January last year...