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

  1. #11
    Senior Member neuroanatomist's Avatar
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    Quote Originally Posted by Daniel Browning View Post
    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?!?

  2. #12
    Super Moderator Kayaker72's Avatar
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    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.

  3. #13
    Super Moderator Kayaker72's Avatar
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    Quote Originally Posted by neuroanatomist View Post
    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.
    Last edited by Kayaker72; 04-07-2012 at 03:12 AM.

  4. #14
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    You're welcome. Glad it worked for you.

  5. #15
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    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...
    An awful lot of electrons were terribly inconvenienced in the making of this post.
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  6. #16
    Senior Member conropl's Avatar
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    Quote Originally Posted by Daniel Browning View Post
    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?
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  7. #17
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    Quote Originally Posted by conropl View Post
    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.

    Quote Originally Posted by conropl View Post
    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.

  8. #18
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    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.
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  9. #19
    Senior Member conropl's Avatar
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    Quote Originally Posted by Daniel Browning View Post
    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.
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