After I bought a Canon EOS 40D I started seeing a bright white spec near the centre on long night exposures. In raw, the converter often hid it. In JPEG it was still there. That is a stuck pixel (bright). A dead pixel is the opposite — a black hole that never reports light.
I did not want to send a new camera back. On a forum I found a sequence that is really Canon’s sensor-mapping routine, hiding in the manual sensor-clean item. I charged the battery, ran it, and the spec was gone from JPEGs. I have used the same steps since.
What to do
- Charge the battery. Do not start this on a dying pack.
- Put the body on a table. No lens change in the middle.
- Open the menu and start Manual sensor cleaning (the option that locks the mirror up / opens the shutter for cleaning).
- Leave it. Wait about thirty seconds. Do not poke the sensor.
- Turn the camera off from the power switch. Let it finish the cycle. Then power on as usual.
The useful part is the power-off. Canon uses that shutdown to remap hot pixels. You are not “cleaning” dust; you are asking the body to ignore a bad photosite.
Bodies this has worked on
I first did this on a 40D. After I wrote it up, people told me it also worked on a long list of EOS bodies, including 100D, 400D / Rebel XTi, 450D, 500D, 550D / T2i, 600D, 700D / T5i, 50D, 60D, 70D, 80D, 7D and 7D Mark II, 5D / 5D Mark II / 5D Mark III, 5DS R, 6D, and EOS M. A few Nikon owners said a similar self-clean / remap helped on their bodies; I cannot verify Nikon myself.
If it does nothing, the spec may be dust on the filter (which this will not move) or a pixel that the map will not cover. Then you clone it in the raw converter or talk to a service centre. For a single stuck pixel on a Canon DSLR, try the menu cycle before you pack the camera for repair.
Comments
Tried this on my 40D after a white speck showed up on long exposures. Manual sensor clean, wait, then power off. Speck was gone from the JPEGs on the next night shoot.
Same stuck pixel on a 600D. First run did nothing. Did the menu cycle again the next day and it remapped. Still clear a month later on 8–10 second frames.
Followed the steps on a 7D. Bright spot is still there. Might be dust on the filter rather than a hot pixel. Will try a proper clean before I send it in.
Worked on my 5D Mark II. One hot pixel near the centre on 30-second bulb shots. After the power-off remap it stopped showing in JPEG. Raw converters were already hiding it most of the time.
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