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)
1,225KB	983KB
100% crop, visible noise.	100% crop, camera much colder the noise is all but gone.
1,108KB	99KB
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

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