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The effect of temperature on CCD's

By dpreview staff on May 3, 2000 at 04:00 GMT

And a great new way to take quality night shots with your digicam (Nikon Coolpix 990 used for these samples). I've known this for a long time, but didn't explore it with the new 3.3 megapixel digicams. The "dark current" noise increases with temperature. Thanks to Dave Martindale for detailing this, "dark current noise is exponentially related to temperature - it DOUBLES for every 6 or 8 degrees C temperature rise (depending on the CCD)."

Taking this practically I took one shot with the camera at room temperature, leaving the camera outside for 20 minutes and took another... the results speak for themselves.

All shots were taken with the camera in Manual mode, Incandescent White Balance, Infinity Focus, ISO 100, F3.6, 8 seconds.

Shots taken at room temperature
(est. camera temperature 24oC)
Shots taken 20 minutes later
(est. camera temperature 10oC)

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100% crop, visible noise. 100% crop, camera much colder the noise is all but gone.

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Black frame, brightened 16 times, 100% crop
 
Black frame, brightened 16 times, 100% crop

As you can see, pretty impressive results. I'll be updating my Coolpix 990 review with these findings, this technique also seems to work very well on the Olympus C-3030Z. Remember the same is true in the reverse, that is during the day if the camera is getting hot you're more likely to see noise in the image than if you were to store it in a shady cool place and / or let it cool down before that important shot.

The importance here is understanding the relationship between temperature and the noise you may see on your images... Knowing that may well help you when you have time to stage the shot.

Warning

Whenever you take the camera between environments of significantly different temperature you MUST let the camera cool down or warm up slowly, and you must NEVER turn the camera on until it has properly acclimatized (about 15 minutes) as you may well damage internal electronics or get condensation into the lens system.

For example, the Operating Environment stated for the Nikon Coolpix 990 is:

  • Temperature: 0 � 40oC (32 � 104oF)
  • Humidity: under 85% (no condensation)

Digital Photography Review accepts no responsibility to damage caused to anyone's camera equipment by this technique. Never use a refrigerator to cool your camera!

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