Hot Pixels on 5D?

[Rynomar]

Hello everyone,

I was recently taking some pictures at night above water and during post processing, I noticed some red, green, and blue spots dispersed throughout the picture. The spots are in the same location on several of the photos. Do any of you know if these are "hot spots". I have read about burnt out pixels that are basically stuck on on color channel. Am I correct in guessing that that is what I am seeing? Other than removing the spots in post-processing, is there anything I can do about it?

Thanks,

Ryan

 

[Rynomar]

Below is a link to a picture with the spots I am talking about. The picture has been cropped and converted to jpg, otherwise it is not modified.

http://www.scubaboard.com/gallery/uploads/76565/hot_spots.JPG

 

[RonFrank]

The short answer to this question is.... photographers have been dealing with Dust (spotting) on prints, lenses, and negatives since the dawn of time. Now we have digital, and photographers now must deal with dead/hot/stuck pixels, and dust! At least we now have tools to do so easily!

Here is a response from Canon on Stuck Pixels:

Good question. This behavior is normal and does not constitute an issue with the CCD. This phenomenon is known as hot pixels. Here's a brief
explanation of what happens:

Because the CCD has millions of photocells (photosites), there is no way to physically ensure that they are all at the same sensitivity to light. The hot pixel phenomenon usually occurs at long shutter speeds, when the CCD is
exposed longer, causing photosites that are more sensitive to light to appear whiteish. They may sometimes be different colors, but are typically
white to the naked eye.

To prevent this from occurring try setting the shutter speed manually to use a faster shutter speed.

Should you require further assistance, please feel free to email us or visit our customer support website at Canon Canada Inc.


Sincerely,

David M.
Technical Support Representative
Customer Information Centre
Canon Canada Inc.

The reality is that the photo's you posted are so abstract, I can't tell if they would be worth working on, or no.

If you camera is under warranty, you could contact Canon. There are a number of things that may help fixing stuck pixels. Oly offered some pixel remapping software a long while back. I think most digital shooters have just come to realize that if they can see a stuck pixel, it's time for a quick PS fix.

In the early 2000's people were making a huge issue over this, now I don't see it as much. Most sensors are not 100% perfect (LCD's as well). So the question becomes what is acceptable? One would have to pose this question to Canon/Nikon/Sony and other sensor manufactues, because I don't know what each defines as acceptable. Sensors can also develop dead/stuck/hot pixels over time.

Since the issue of stuck pixels is mainly doing long exposures, often at night, this is not big for most. Stuck pixels can also become unstuck, and they may not be noticeable when shooting in daylight conditions. Dead pixels however don't come back to life, and will be noticeable in daylight shots.

Good Luck,

 

[Rynomar]

Thanks for the information. It has not been an issue at all and this is the first time I have noticed it. I will just have to be aware of it in the future.

Thanks again.

 

[bladephotog]

Is it still doing it? Because this can sometimes happen when pushing the envelope exposure-wise, which looks like what you did with this photo. If it's happening on every picture, especially well-exposed images, then you might have a problem.

 

[bigfrog23]

those spots in the sky might might be stars that are just starting to appear if they are not and they are actually hot spots you should call canon and see what they say they might replace it even if it is out of warranty

 

[SCUBASTEVEN]

For some reason I am unable to see your pic, however, as a camera repair tech I can tell you that if you are seeing the red and green spots send it in to Canon to fix. That going to be the only way to stop it from happening. Sorry.

 

[Rynomar]

The response that RonFrank posted describes the shooting conditionsof the photo pretty accurately. This is the first time that I have noticed the spots in a photo, however I have not taken many photographs at night.

The photo was taken right after a snow storm in central Utah. The sky was overcast and the spots are visible throughout the picture. I have posted a copy of one of the photographs. The spots are most apparent in the photograph taken at ISO 160 with 45 seconds of exposure.

I am going to try taking some more pictures in a dark environment at different ISO's and shutter speeds to see if the spots are going to be an issue. Thanks again for the help.


http://www.scubaboard.com/gallery/showphoto.php/photo/93317/ppuser/76565

 

[Rynomar]

I just did a little looking on DPReview and found some good information. Activating C. Fn. 02 (long exposure noise reduction) virtually eliminated the hot spots. Also, you can check for hot spots by taking a picture with the lens cap on.

Set the shutter speed in the range from 1 second to 30 seconds at various ISO's to identify the hot spots. With the noise reduction turned on the hot spots were cleared. The camera reads the sensor for the same amount of time that the shutter was open so it does slow down the speed of the camera. Hopefully this will help.