9.  Removing noise caused by long exposure times.

Many recent Nikon Digital cameras (950, 990, D-1) offer the possibility of long exposure times to capture images in extremely low light conditions.
The image used in this example (the Half-Dome in Yosemite, CA) was taken by moonlight in August 2000.

	This image was taken with an 8 second exposure. The crop is about 50% of the original image, resized down to 300 pixels wide and saved with a JPEG compression setting of 5.  The effects of the noise on the original can be seen as JPEG artefacts.
	This is the same image, cropped, scaled and saved after noise filtering
	This crop from the original image with no scaling  shows the visible effect of noise generated by the long exposure time.
	The same crop, after filtering with the Photoshop™ "Dust and Scratches" filter.
	The Photoshop™ Dust and Scratches filter, used to reduce the effect of noise in the final image. Note that other techniques such as converting the image to Lab format, filtering the L channel and blurring the a and b channels is also effective.