SOUND OFF ~ How many dead pixels...

jaetee

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... does your camera have? and how old is your camera/model?

4 dead pixels, 16 month old Canon 20D

Trying to figure out how common this is...

jt

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Lots of Cameras, lots of lenses, not enough time... see profile for a semi-current equip list.
 
... does your camera have? and how old is your camera/model?

4 dead pixels, 16 month old Canon 20D

Trying to figure out how common this is...
Dead - you mean at al ISO and shutter speeds (always there)?
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Misha
 
... does your camera have? and how old is your camera/model?

4 dead pixels, 16 month old Canon 20D

Trying to figure out how common this is...
Canon sensor = 3504x2336
=8,185,344 pixels
  • 4 dead pixels
= 8,185,340 pixels.

Yes, I can see how there would be image degradation.

Hot pixels, OTOH, do need to be addressed and mapped out of the usable space.

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Gary
 
Yes, at all ISOs there are always 4 pixels that appear as white specs. Not really what I'd consider it a problem, I'm just curious how many people have noticed this and if its very common.
... does your camera have? and how old is your camera/model?

4 dead pixels, 16 month old Canon 20D

Trying to figure out how common this is...
Dead - you mean at al ISO and shutter speeds (always there)?
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Misha
--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Lots of Cameras, lots of lenses, not enough time... see profile for a semi-current equip list.
 
... does your camera have? and how old is your camera/model?

4 dead pixels, 16 month old Canon 20D

Trying to figure out how common this is...
I have none in either the 300D or the 20D. The 300D was a first batch, so it's old. The 20D is from this past december.

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It's me.
I just checked.
 
Thanks for the math lesson. Never said there was degradation or that I considered it a problem....

I have 4 pixels that show up as solid white at all ISOs. Especially noticeable when the background is solid black. I'm just curious if others have noticed the same.

What would you consider the difference between a dead pixel and a hot pixel.

jt
... does your camera have? and how old is your camera/model?

4 dead pixels, 16 month old Canon 20D

Trying to figure out how common this is...
Canon sensor = 3504x2336
=8,185,344 pixels
  • 4 dead pixels
= 8,185,340 pixels.

Yes, I can see how there would be image degradation.

Hot pixels, OTOH, do need to be addressed and mapped out of the
usable space.

--



Gary
--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Lots of Cameras, lots of lenses, not enough time... see profile for a semi-current equip list.
 
I have 4 pixels that show up as solid white at all ISOs. Especially
noticeable when the background is solid black. I'm just curious if
others have noticed the same.
A 300D about 18 months old. Also zero in a S45 that is several years old.

I'd find solid white pixels real aggravating. After I got my S45, I thought I had some white pixels, but I eventually figured out it was just specular highlights from shooting snow on a bright, cloudless day.

Wayne Larmon
 
As above. In long exposures without noise reduction there're a few hot (white, in fact) pixels, but they don't show up in prints and noise reduction totally eliminates them.

7 month old 350D.
... does your camera have? and how old is your camera/model?

4 dead pixels, 16 month old Canon 20D

Trying to figure out how common this is...
Dead - you mean at al ISO and shutter speeds (always there)?
--
Misha
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After 11 months my 20D developed two bad bright hot pixels - one white pixels that showed up at all shutter speeds, and ISOs and got brighter the higher the ISO and the longer the shutter speed - another was also there at all shutter speeds on ISO 400 and up, plus a few other fainter white pixels that required long exposures and high ISOs. Canon mapped the worst of them out for me under warranty. But usually I shoot RAW and use ACR and that removes hot pixels automagically.

The loan 10D I had (Canon owned) while my 20D was being repaired, had more than one white and one red hot pixel, which appeared at ISO 400 and up, normal shutter speeds. So I guess one can say it's something that is fairly commmon. If it really bugs you Canon can map them out so they don't appear in jpegs. Mine didn't show up in large prints but did show up in slideshows on a 20 inch screen so they did need to be cloned out or otherwise dealt with on the odd occasion when I used something other than ACR to process my images..
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Some of the least worse of my photos:
http://www.flickr.com/photos/susans/
 
like give us a simple utility to map hot pixels ourselves, whenever we want to do it, and without having to pay for the shipping fees, hourly service rate and be without our cameras for weeks... when you know the 5D has a "shy" hot-pixel mapping routine built into the sensor cleaning procedure... it's there, so it's doable in camera and on demand. Alas, it's "shy" in that it only maps automatically what it thinks is objectionnable, and you can't control how much or what is being mapped out.

I had a pack of purple pixels when I bought my 5D. Got them imprinted over 800 pics of a wedding (blue on black tuxedos, yummy). A few days later, I didn't notice it but they've disappeared from all the photos taken after, supposedly, a sensor cleanup procedure. Damn, I should have triggered the sensor clean routine sooner.

Still, I'd like to be able to designate the pixels I want mapped myself . Doing that on the computer could prove to be a nice and simple way to avoid all the returns for bad pixels, and the clogging of Canon's service centers that slows down other customers' important issues.

Olympus does it in camera, why not Canon? Of course 4/6 blue pixels out of 12.700.000 is negligible... but whenever there's a dark background, it's a PITA to clone out of each jpeg image (no I don't shoot RAW so ACR can't treat them for me).

Guillaume

' Most americans aren't racist or stupid. Why should I be burning cars, or dissing americans? Just because I'm french? '
 
difference would be exactly as it sounds...

dead = zero output - "black"

hot = constant output

There is a difference. dead pixels can be ignored, hot ones can't and must be mapped out (made dead) by a service tech.

My apologies for misunderstanding.
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Gary
 
my 20D is about a year old and there is 1 red pixel which always appears at the same spot regardless of ISO or exposure time.

Not always noticeable in the pictures though.
 

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