Dead pixels test.

[coffee]

I found this on a different forum that might be of interest here.

Most digital camera sensors had hot or dead pixels. There is a way that canon camera can "reset" hot pixels that show up on your pictures. I don't know about other makers, but for canon the proceedure is to lens cap the camera, go into the menu and choose sensor cleaning which will lift the mirror. Wait up to 30 seconds or so, then turn the camera off. For some reason this will reset the hot pixels to normal.

One way to tell that you have hot pixels is to take a pic with the lens cap on so that the picture is completely black. Usually a longer exposure, say 2-3 seconds. Then look at it to see if there is red, blue or green dots on the black pic.

Here is a very small and free program that looks at these pics and can find all the hot and dead pixels.

http://www.starzen.com/imaging/deadpixeltest.htm

[jerryph]

For my Nikon D200, you only see hot or dead pixels on very long and dark or bright exposures.

Nikon has no in-camera method, but if you send your camera to them, they can map out the dead pixels with ones that are not defective. Of courses there is a limit to the number of times this can be done, but it is not something that they let users do, as it requires some proprietary software.

On the newest D300's there seems to be more dead pixels on new units than average, but I am really happy to say that on my D200, I do not have any dad pixels... at least none now. We know that all digital cameras get them sooner or later. All hail the healing brush tool in Photoshop... lol.

[coffee]

Canon doesn't advertise the in camera fix either for some reason, but the procedure I described is one a user stumbled apon, but does work great for some reason.

[dkippen]

I have never heard of anything like this. Learned something new today, and I'll have to give it a try.

Joseph - BTW, did you get my PM??

[coffee]

Thank you for the PM Debbie. No I hadn't noticed it before you said something. That sounds like something I would certainly be interested in. I live very close to MV School too.

Thanks again, you're the best!!

[dkippen]

I'll be there - I'm going with the photo instructor, she says these are very good. BTW, if you haven't heard of them, I belong to the N. Metro Photo Club. Let me know if you want more info.

[johnc24]

hey guys

I done the test where you take a "black" photo and I didn't spot ny dead pixels. but when I ran some photos through the software link it gave a result of one photo as 13018 Dead Pixels / 9050975 hot pixels.

Can someone interpret this for me.

Thanks

Regards
John

[coffee]

Run the dead pixel test with a "black" photo as well. You can't run it with a shot with an image on it. Read the readme in the deadpixeltest program folder.

[johnc24]

Hi Joe

Thanks for the info

I did it with the black image and got a 0 on both counts so thats good.


regards
John

[coffee]

Ya that's great John. How old and what kind is your camera?

[johnc24]

Hi joe

its a canon 400D/Xti

only a few months old now but It never does any harm to test it anyways, but it seems like its all set.

regards
John

[ladyups]

Well, dang...something else I need to be watching for...I just got over the dust spots and now I've got to look for dead pixels...does it ever end?