Hot Pixels on your Sensor?

[Andy M]

Last night while shooting pictures of my girlfriend, I noticed a reoccurring hot pixel. It's tiny, but annoying all the same.

You can see it here on the hair which falls in-between my girlfriend's bosom:



While waiting to talk to somebody at my local Canon repair centre I tried searching the net to see if fellow Canon owners had experienced the same problem. They had, in their droves - it appears it's accepted that if your camera is less than a few months old then hot pixels are to be expected :huh:

Then, I fell upon this post: http://forums.dpreview.com/forums/rea

The important parts being:

DPReview said:

...with the lens on the camera and the lens cap on the lens, and the lens pointing to the floor, I activated the 'Sensor Clean' function for about 30 seconds. (Obviously with a lens on, I made no effort to clean the sensor before, after or during this operation!). At the end of the 30 seconds, I switched the camera off to close the shutter and return the mirror...

and

DPReview said:

I am now of the opinion that operating the sensor clean function with a lens on and a lens cap on the lens, causes the camera to either map out hot/stuck pixels, or to reset itself, neutralizing them. Pure speculation of course, but it solved the problem completely in 30 seconds. (N.B. I did not clean the sensor at any point and have never done so.)

It worked on my 5D, it may work for you too

[matthew_h]

I've got two bright red hot pixels on my 20D that show up on long exposures.

They're irritating but can be sorted easily enough in PS.

Will try that trick though to see if it helps. Sounds like it shouldn't but has got to be worth a try.

Cheers

[Andy M]

Let me know how you get on

[matthew_h]

Damn, I thought you might try it first and then let us know.

It sounds utterly implausible to me but also doesn't sound like it could do any harm.

[Andy M]

"It worked on my 5D, it may work for you too"

It worked, no problems

[matthew_h]

Doh, missed that.

Fair enough then. Will give it a crack.

Cheers Andy

[monkeyhanger]

I seem to recall reading somewhere that the more recent Canons can actually "map out" hot pixels although i don't know the procedure for this.

[mr noble]

Nikon's don't suffer this problem.

[Andy M]

mr noble said:

Nikon's don't suffer this problem.

Neither do Canon's

I presume you're talking about film cameras, as all digital cameras will suffer this same problem. It's just that Canon's digital camera's are clever enough to map them out automatically, the question is; are Nikon's?!

[davidy]

Having worked in machine vision for years, it is very difficult to make a perfect large sensor. Years ago Kodak used to grade sensors for their scientific cameras and a grade 1 3kx2k camera was around £50K

If you know where the oixels are, then you can usually make good assumptions about the content of that pixel from its nearest neighbours, this can be done in an automated manner. Easiest way to find out if your camera can do it is to take a picture with the lens cap on!

davidy

[fergusd]

Andy M said:

mr noble said:

Nikon's don't suffer this problem.

Neither do Canon's

I presume you're talking about film cameras, as all digital cameras will suffer this same problem. It's just that Canon's digital camera's are clever enough to map them out automatically, the question is; are Nikon's?!

Yeah . . . every time you take a picture ;-)

Fd