# How Hot Are Your Pixels?



## Stan (Aug 7, 2003)

As you may know, I bought a used Nikon Coolpix 990. It came from a retailer that offers an extended warranty on used equipment and I took advantage of that warranty as the price is very reasonable compared to the cost of digital camera repairs. Kodak, for example, has a basic service charge of Â£120 and other manufacturers will be charging the same.

I donâ€™t want you digital camera users to get paranoid but take a look at this:-

http://webpages.charter.net/bbiggers/DCExp...hot_pixels.html

Hot pixels are well known and normally nothing to get worried about unless they encroach into higher shutter speeds, say 1/30th of a second. If a pixel is â€œstuckâ€ and apparent in normal daylight shots it should be attended to if the camera is still in warranty. IMO

A manufacturer will not normally replace the CCD of the camera unless the situation is particularly bad, it will instead re-map the camera firmware to exclude those bad pixels from the overall interpolation (this is done at the factory when the CCD is new). A bit like excluding bad sectors like hard drive manufacturers do.

If you donâ€™t have any warranty left on you camera or you have bought a used camera then you will have to get it fixed and pay for it.

The hot pixel paranoia has been around for a while and is not the problem that many people like to make out. A couple of obtrusive pixels on a 1 second exposure is not a major problem IMHO, how many long exposures do YOU take?

I found a couple of hot (not bad) pixels at Â¼ of a second on my new (old) Nikon and I do take quite a few shots at this low speed to get the depth of field I need.

I do have a warranty but donâ€™t want to send the camera away four 4 weeks to get it fixed having had it for less than a week.

I found a piece of software that is useful for users of certain coolpix cameras called Cpix 2.4. I wonâ€™t post a link because you can find it quite easily by Googling.

You see, this software has another talent. It can detect hot pixels and re-map the CCD. This is not official Nikon software and could, if incorrectly used, damage a camera and present you with a big bill. Read the words and use at you own risk.









So I did. I used it because I have a warranty to fall back on and I had heard good reports of it when used on the cameras itâ€™s designed for.

Result, no visible hot pixels at a 4 second exposure!









Ok, thatâ€™s good but what is the point of this post? If any of you are thinking of buying a used digital camera, be careful. I would not buy one privately because of the cost of repairs if you find a â€œminorâ€ fault in your purchase. Many private sellers may not even be aware that the camera that they are selling has a fault, some will.









Buy from a retailer and insist on a warranty for as long as possible even if you have to pay for it.

Donâ€™t get paranoid about hot pixels, most digital cameras have some, those that donâ€™t will get some as time passes. Itâ€™s only a problem if dodgy pixels interfere with your photography.


----------



## MIKE (Feb 23, 2003)

Hi Stan,

Thats intresting, never heard of them before







I will have to fetch the back off and see if I can find any









MIKE..


----------



## Stan (Aug 7, 2003)

Mike, you are a true "Bugger".
















I'm in a technical mood tonight, just ignore me.


----------



## MIKE (Feb 23, 2003)

Stan said:


> I'm in a technical mood tonight, just ignore me.


 Your not wrong there







I have just read your piece on compresion, now I'm really confused
















MIKE..


----------



## geoff (Jul 29, 2003)

Hi Stan

These hot pixels are they the same as Hot dixies cos if they are anything like The Dixie chicks i would'nt mind having some exposure with them.

Geoff


----------



## Stan (Aug 7, 2003)

Geoff,

Join the BAC please.
















Mike,

I'm always confused.


----------



## geoff (Jul 29, 2003)

Stan

Is that a compliment or an insult.

Geoff


----------



## Stan (Aug 7, 2003)

Geoff,

You decide.









I meant it as a compliment judging by the the caliber of "buggers" we have on board at the moment.


----------



## 1madman1 (Apr 14, 2004)

My Canon A70 has what looks like a stuck pixel, but the strange thing is it only appears about ~20% of the time. I'm guessing it's not a CCD problem.


----------



## geoff (Jul 29, 2003)

Stan

Some one likes my Humour!!!! Ehhhhh!!!

Geoff


----------



## Stan (Aug 7, 2003)

I've been doing some research and practical testing on hot pixels (noise).

That's why I haven't been on the forum much.







You can all stop cheering now.
















Temperature has a significant bearing on the number of hot pixels exhibited, if a camera has been in use for 15 minutes the number of hot pixels is much more evident.

I've tested this and some may be alarmed at the results, we are talking thousands of them.









I cooled the camera in the fridge for half an hour and repeated the test at 8" and no hot pixels.









This is only an issue for those that want to do long exposure photography with a digital camera and should not concern any one but astronomers and idiots like me.

Those like me that want to take long exposures can remedy hot pixels in post production or may be lucky enough to a camera with a good noise reduction system.

I'll keep the old Nikon cool.


----------



## AlexR (May 11, 2003)

Is a hot pixel opposite to a cold gnome?


----------



## Stan (Aug 7, 2003)

Not Lord Gnome?









Private Eye reference.


----------



## AlexR (May 11, 2003)

No mine are NHS


----------



## Stan (Aug 7, 2003)

The HNS does gnomes?









I know it does dwarfs, because Shorty went.


----------



## AlexR (May 11, 2003)




----------



## pg tips (May 16, 2003)

Stan I worry about you! Would the fridge not cause condensation inside the camera? Might bugger it up totally.


----------



## AlexR (May 11, 2003)

How do you get a fridge inside a camera?


----------



## Stan (Aug 7, 2003)

PG,

Don't worry.









Plastic bag and silica gel.


----------



## Stan (Aug 7, 2003)

Alex,

Silly arse.


----------



## AlexR (May 11, 2003)




----------

