Hot pixels ? no problem (almost)

[ralph-FR]

If you've watched Reverie or Alan Doyle's demo clip, you've probably seen them in their full stationary glory : hot pixels.

Hot pixels are a part of a digital camera's life. As it gets old, you have more of them. Ironically though, new cameras can have some (I won't give names!)

Canon, in their infinite greatness, still haven't been smart enough to save on service costs and offer us a way to mask them manually in-camera once and for all (like they recently gave us a way to calibrate the AF ourselves instead of sending cameras for service and getting them back "not tuned like we wanted" and be angry or just plain sell bad pictures which is more annoying).

In 2005 my new 5D had a nasty pack of 4 purple pixels on every photo. Just 4 days and 1 wedding later, I was * : my new camera was defective and was giving me extra work in Photoshop to mask those sweeties from my pics.
Later on, I don't know why, I take new pics and prepare myself to launch Photoshop... but they're missing from ALL pics.

WTF ?

It turns out I had cleaned my sensor using the menu option a few days ago. People shared their thoughts and observations... it was confirmed by many, that during a manual sensor cleanup routine, the 5D apparently does some black magic on hot pixels and actually kills them if you're lucky. That's supposedly why there's a 1 second delay between your launching the procedure and the camera opening the mouth (other cameras of 2005 such as the 20D and older simply open the mouth the moment you press the set button, there's no delay).

The good : hot pixels are less of a fatality.
The bad : there's no warranty that the camera will detect the bugger(s) and actually map them out. You may have to repeat the procedure a few times, or even do a good, lenghty bulb exposure to heat up the sensor so the hot pixels are more visible.
The ugly : while fixing some, the camera can also unmask previously cured pixels. Yes, after a cleanup you might have more hot pixels !
The mother of all uglies : it doesn't work for video mode.

Conclusion : use that manual sensor cleanup feature only when needed, only when you have bad pixels to kill.
To actually clean the sensor, shoot a 30" exposure with a clock nearby, do your brush/swab thing and back off before the camera closes its mouth. Rinse, repeat...

And as always, write Canon a delicious love letter telling them how much you love to rely on an obscure, undocumented, automatic procedure to avoid ruining all the pics you take with that otherwise wonderful camera. Request a manual mapping feature like all Olympus cameras have.

I recall seeing a thread like that on dpreview. I seem to remember Canon alleging that no such function actually exists.

[ralph-FR]

Canon alleging that no such function actually exists.

They don't want to admit their sensors (like all sensors) are not perfect... but it works.

5 minutes ago I had a red pixel on my 5D. I take a pic at ISO3200, 1". It's there. I trigger the sensor cleanup, switch the camera off then on, retake a pic with the same settings, it's still there.
I shoot a 3 minute bulb exposure, then I run the sensor cleanup and retake the 1" pic.

The pixel is gone. They can say all they want, I believe what I see