Hot or dead pixels ?

Pablo · 7th June 2006

Hello all,

I took my 20D in for a sensor clean today and had a good chat with the camera tech.

Apart from other things discussed (like $83 is a lot to pay for a clean

), I mentioned dead pixels.

"I had noticed a few either HOT or dead pixels when zooming in on a night photo I had taken".

I had also mentioned that I have used the camera for IR and that exposure times have been quite long.

He then said that the cause of the faulty pixels is likely due to long exposure times because they can tend to cook if long exposures are used frequently.

What are your thoughts on this ? .... and Panda, I am not trying to scare you

As some may know, I don't use the 20D for IR now but use a D70 because of the MUCH shorter exposure times required.

Cheers

ark19 · 7th June 2006

Bro, you might want to try this to check for dead or bright pixels:
http://www.starzen.com/imaging/deadpixeltest.htm
Follow the instructions.

Pablo · 8th June 2006

Hi ark19,

Thanks for the program.

An interesting program it is too.

I tried various shutter times and found that I have NO dead pixels.

But it does show that I have around 275000 HOT pixels

Cheers

Qazwer · 8th June 2006

Hi Pablo,

Is there any difference between CCD and CMOS sensor in terms of likelihood of Hot or Dead pixel?... As in durability after long exposure?

ark19 · 8th June 2006

No prob Bro

Hmm... last time found an article on adding a cooling fan to DC to cool down the CCD, maybe you can try that

Qazwer · 8th June 2006

Bro, I mean, it is higher chances of getting hot and dead pixel in CMOS when compared CCD.

Haha ... can you help me with the mod?

smtan24 · 8th June 2006

Originally Posted by ark19

No prob Bro
Hmm... last time found an article on adding a cooling fan to DC to cool down the CCD, maybe you can try that

Is this the image of the cooling fan:

eawtan · 8th June 2006

Checkout some hot pix fixes ...

http://www.redpawmedia.com/hotpixel.html
http://www.berfield.com/plugin.html

Pablo · 8th June 2006

Hi smtan24,

Could not see your picture.

I decided to strap a bag of ice to the top of my camera untill I can find a good source of a small freon pump

Hey ark19, would it have used a Peltier Device by any chance

Cheers

ark19 · 8th June 2006

Originally Posted by Pablo

Hi smtan24,

Could not see your picture.

I decided to strap a bag of ice to the top of my camera untill I can find a good source of a small freon pump

Hey ark19, would it have used a Peltier Device by any chance

Cheers

Hey Bro,
that's a good idea, but for the one I saw, the modder actually cut a hole and use a small pc fan to cool the DC.
Peltier might actually work

ark19 · 8th June 2006

Originally Posted by smtan24

Is this the image of the cooling fan:

Wah, this looks extreme!
The one I saw was much smaller...

Pablo · 9th June 2006

Hi ark19,

I don't know why but I still cant see the photo.....

Anyway, I really thought you guys were just kidding. Really !!!

Would cooling actually assist in any way with hot pixels ?

Even if it could, adding a fan would be blowing dust in and around everywhere.

Dust bunnies would be more of a problem than hot pixels.

By the way, the reading of 275000 hot pixels doesn't mean much to me as I cant see them in my photo's anyway
unless I do night shots of the moon and then look very closely at every mm of the frame zoomed in very close.

Cheers

Qazwer · 9th June 2006

Hi Pablo,

I don't know if it works either. I can't view the pics too.

If it's true, how about reverse mount the fan and blow out the heat and dust particles?

wildstallion · 9th June 2006

Originally Posted by Qazwer

Hi Pablo,

I don't know if it works either. I can't view the pics too.

If it's true, how about reverse mount the fan and blow out the heat and dust particles?

Yeah, but then you are not replacing the hot air with cool air and therefore no cooling will take place

Qazwer · 9th June 2006

Originally Posted by wildstallion

Yeah, but then you are not replacing the hot air with cool air and therefore no cooling will take place

Huh? Isn't the hot air been drawn out of the camera?

wildstallion · 9th June 2006

Originally Posted by Qazwer

Huh? Isn't the hot air been drawn out of the camera?

Yes, but nothing is replacing it, so the sensor will still remain at the same temp, wont it?

Pablo · 9th June 2006

Hi guys,

I don't have a problem "to me" with hot pixels unless it mucks up a normal photo.

Personaly, I would not take any notice about cooling fans or any other radical method.

All cameras I am shure will have hot pixels at some time in there life, but wether it will make any difference to your shot is small.

Remember, your camera has 6 million or more pixels. It will take a lot in one place to become noticable.

It is very different to an LCD 17" monitor where if you notice just one dead (not hot) pixel, you will always be aware of it.

So, guys, DON'T be worried about your pixels unless someone that looks at your photos points and says, "that pixel is wrong".

Remember, they are pointing at one or two dots within 6 to 10 million... lots of luck there.

Cheers guys, just shoot more.

It was an interesting discussion

Qazwer · 9th June 2006

Originally Posted by Pablo

Hi guys,

I don't have a problem "to me" with hot pixels unless it mucks up a normal photo.

Personaly, I would not take any notice about cooling fans or any other radical method.

All cameras I am shure will have hot pixels at some time in there life, but wether it will make any difference to your shot is small.

Remember, your camera has 6 million or more pixels. It will take a lot in one place to become noticable.

It is very different to an LCD 17" monitor where if you notice just one dead (not hot) pixel, you will always be aware of it.

So, guys, DON'T be worried about your pixels unless someone that looks at your photos points and says, "that pixel is wrong".

Remember, they are pointing at one or two dots within 6 to 10 million... lots of luck there.

Cheers guys, just shoot more. It was an interesting discussion

Well said!

More at ease now.

ark19 · 9th June 2006

Actually hot pixels are more of a prob for DCs and not DSLRs.
For DCs the CCD is always on for previewing the scene in the EVF of LCD. For DSLRs, the ccd is only sw on for a short while to capture the image.

For mounting of the fans, dust is not a problem as the consumer DC CCD is usually a sealed unit

7th June 2006	#1
Pablo Senior Member Join Date: Sep 2004 Location: Blue/Green Planet Posts: 1,855	Hot or dead pixels ? Hello all, I took my 20D in for a sensor clean today and had a good chat with the camera tech. Apart from other things discussed (like $83 is a lot to pay for a clean ), I mentioned dead pixels. "I had noticed a few either HOT or dead pixels when zooming in on a night photo I had taken". I had also mentioned that I have used the camera for IR and that exposure times have been quite long. He then said that the cause of the faulty pixels is likely due to long exposure times because they can tend to cook if long exposures are used frequently. What are your thoughts on this ? .... and Panda, I am not trying to scare you As some may know, I don't use the 20D for IR now but use a D70 because of the MUCH shorter exposure times required. Cheers __________________ Time, is an effortless construction :)

7th June 2006	#2
ark19 Senior Member Join Date: Jan 2002 Location: ark19.multiply.com Posts: 3,080	Re: Hot or dead pixels ? Bro, you might want to try this to check for dead or bright pixels: http://www.starzen.com/imaging/deadpixeltest.htm Follow the instructions.

8th June 2006	#3
Pablo Senior Member Join Date: Sep 2004 Location: Blue/Green Planet Posts: 1,855	Re: Hot or dead pixels ? Hi ark19, Thanks for the program. An interesting program it is too. I tried various shutter times and found that I have NO dead pixels. But it does show that I have around 275000 HOT pixels Cheers __________________ Time, is an effortless construction :)

8th June 2006	#4
Qazwer Member Join Date: Sep 2005 Location: My beautiful earth Posts: 1,569	Re: Hot or dead pixels ? Hi Pablo, Is there any difference between CCD and CMOS sensor in terms of likelihood of Hot or Dead pixel?... As in durability after long exposure?

8th June 2006	#5
ark19 Senior Member Join Date: Jan 2002 Location: ark19.multiply.com Posts: 3,080	Re: Hot or dead pixels ? No prob Bro Hmm... last time found an article on adding a cooling fan to DC to cool down the CCD, maybe you can try that

8th June 2006	#6
Qazwer Member Join Date: Sep 2005 Location: My beautiful earth Posts: 1,569	Re: Hot or dead pixels ? Bro, I mean, it is higher chances of getting hot and dead pixel in CMOS when compared CCD. Haha ... can you help me with the mod?

8th June 2006	#8
eawtan Member Join Date: Feb 2004 Location: Tampines Posts: 1,090	Re: Hot or dead pixels ? Checkout some hot pix fixes ... http://www.redpawmedia.com/hotpixel.html http://www.berfield.com/plugin.html

8th June 2006	#9
Pablo Senior Member Join Date: Sep 2004 Location: Blue/Green Planet Posts: 1,855	Re: Hot or dead pixels ? Hi smtan24, Could not see your picture. I decided to strap a bag of ice to the top of my camera untill I can find a good source of a small freon pump Hey ark19, would it have used a Peltier Device by any chance Cheers __________________ Time, is an effortless construction :)

9th June 2006	#12
Pablo Senior Member Join Date: Sep 2004 Location: Blue/Green Planet Posts: 1,855	Re: Hot or dead pixels ? Hi ark19, I don't know why but I still cant see the photo..... Anyway, I really thought you guys were just kidding. Really !!! Would cooling actually assist in any way with hot pixels ? Even if it could, adding a fan would be blowing dust in and around everywhere. Dust bunnies would be more of a problem than hot pixels. By the way, the reading of 275000 hot pixels doesn't mean much to me as I cant see them in my photo's anyway unless I do night shots of the moon and then look very closely at every mm of the frame zoomed in very close. Cheers __________________ Time, is an effortless construction :)

9th June 2006	#17
Pablo Senior Member Join Date: Sep 2004 Location: Blue/Green Planet Posts: 1,855	Re: Hot or dead pixels ? Hi guys, I don't have a problem "to me" with hot pixels unless it mucks up a normal photo. Personaly, I would not take any notice about cooling fans or any other radical method. All cameras I am shure will have hot pixels at some time in there life, but wether it will make any difference to your shot is small. Remember, your camera has 6 million or more pixels. It will take a lot in one place to become noticable. It is very different to an LCD 17" monitor where if you notice just one dead (not hot) pixel, you will always be aware of it. So, guys, DON'T be worried about your pixels unless someone that looks at your photos points and says, "that pixel is wrong". Remember, they are pointing at one or two dots within 6 to 10 million... lots of luck there. Cheers guys, just shoot more. It was an interesting discussion __________________ Time, is an effortless construction :) Last edited by Pablo; 9th June 2006 at 09:18 PM.

9th June 2006	#19
ark19 Senior Member Join Date: Jan 2002 Location: ark19.multiply.com Posts: 3,080	Re: Hot or dead pixels ? Actually hot pixels are more of a prob for DCs and not DSLRs. For DCs the CCD is always on for previewing the scene in the EVF of LCD. For DSLRs, the ccd is only sw on for a short while to capture the image. For mounting of the fans, dust is not a problem as the consumer DC CCD is usually a sealed unit