Sensor Problem?

CanAm

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So, I was screwing around, taking pictures of the ember on the end of an incense stick, and I noticed these bright splotches of light here and there in the pictures. I thought it was strange and set a 30 second exposure with the lens cap on and took a pic, and I got the same result.

Whats the issue here? Does my sensor need a cleaning, or what?

http://i16.photobucket.com/albums/b35/airsoftsilent/IMG_0449.jpg

http://i16.photobucket.com/albums/b35/airsoftsilent/IMG_0456.jpg

EDIT- being told by a friend that it's just pixel noise from lack of light. Can someone verify this?
 
I must ask others further: are those the dreaded "dead pixels" then? If they show like this in a photo taken with the lens cap on? But why would they be in red and blue colour?
 
Indeed they are in logical groups (RGBG). They die white if all 4 in a group fail which happens often.

There are 2 half truths here. Yes it's noise, and yes it's a dead pixel. But it's not permanently dead. Pixels will give up in a predictable way as the exposure length increases. Be thankful you have so few at 30 seconds.

The fact that they die predictably is a good thing. Long exposure noise reduction is a system available in most cameras whereby the camera clears the sensor after exposure, takes another exposure without opening the shutter, and then does a pixelwise subtraction of the two images. Since the death of a pixels is predictable given the exposure all the specs should be reduced.
 
Indeed they are in logical groups (RGBG). They die white if all 4 in a group fail which happens often.

There are 2 half truths here. Yes it's noise, and yes it's a dead pixel. But it's not permanently dead. Pixels will give up in a predictable way as the exposure length increases. Be thankful you have so few at 30 seconds.

The fact that they die predictably is a good thing. Long exposure noise reduction is a system available in most cameras whereby the camera clears the sensor after exposure, takes another exposure without opening the shutter, and then does a pixelwise subtraction of the two images. Since the death of a pixels is predictable given the exposure all the specs should be reduced.

Is that what my digital is doing when I use it for long exposures....I takes the image and then acts like it is taking another one directly after it, the number of repetes varies with duration.

This is an odd thought to me as I did not understand what was happening, this explanation makes perfect sence except for one thing, the particular camera, Kodak sacrificed a ton of features and took a handfull of shortcuts in development of my digital camera and it seems unlikely that it would have any noise reduction at all.

Sorry I don't mean to hijack this, but I am very curious.
 
Indeed they are in logical groups (RGBG). They die white if all 4 in a group fail which happens often.

There are 2 half truths here. Yes it's noise, and yes it's a dead pixel. But it's not permanently dead. Pixels will give up in a predictable way as the exposure length increases. Be thankful you have so few at 30 seconds.

The fact that they die predictably is a good thing. Long exposure noise reduction is a system available in most cameras whereby the camera clears the sensor after exposure, takes another exposure without opening the shutter, and then does a pixelwise subtraction of the two images. Since the death of a pixels is predictable given the exposure all the specs should be reduced.

So in other words, I have nothing to worry about, correct?

Will this affect daytime shooting at all?
 
So in other words, I have nothing to worry about, correct?

Will this affect daytime shooting at all?

It probably won't affect daytime shooting, but it will probably also be worse at higher ISO with long exposures. This is normal behavior for sensors during long exposure times, newer sensors seem to do a better job,or just have better NR, but I don't think that you have a problem. Take a few shots at ISO 100, with the lens cap on, at different shutter speeds; you probably won't see the hot pixels, and I you don't see them in normal shots, than don't worry about it. And If you really need tho feel better about it, I can post some long exposures from my Olympus E-10; It has HORRIFIC hot pixels.;)

Ryan
 
So in other words, I have nothing to worry about, correct?

Will this affect daytime shooting at all?

Correct and no it shouldn't. If it does it during a fast exposure you really do have a stuck pixel. This is definitely not unheard of.

Is that what my digital is doing when I use it for long exposures....I takes the image and then acts like it is taking another one directly after it, the number of repetes varies with duration.

This is an odd thought to me as I did not understand what was happening, this explanation makes perfect sence except for one thing, the particular camera, Kodak sacrificed a ton of features and took a handfull of shortcuts in development of my digital camera and it seems unlikely that it would have any noise reduction at all.

Easy way to find out. If the processing takes just as long as the exposure then that's what it's doing. Take a 4 second picture and find out. Shortcuts are feature shortcuts, often requested by some numbnuts in a marketing department. Noise reduction is a VERY marketable feature. It would take a special kind of person to omit this feature from a camera :er:
 

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