Images below are 100% crops from the Nikon Coolpix L100. Since this digital camera does not offer any controls over ISO, the two crops below were taken using Auto and High-ISO. In Auto mode, the camera selects an ISO from 80 to 800. In High-ISO mode, the camera selects from 720 to 3200 but image resolution is reduced to 3 megapixels only. The day scene was rather bright so the Coolpix L100 chose the lowest ISO setting in each mode. The night scene was dark enough for the camera to choose its highest ISO settings.

The ISO 80 setting is quite clean with a reasonable amount of details and software sharpening added, most likely to compensate for noise-reduction. Check the edge of the white column to see sharpening at work. ISO 720 looks quite difference. Not only is the resolution much lower, but so are details, even for a 3 megapixels image. Noise is actually low as a result of strong noise-reduction, which is what eats away details. Still, a small print (say 4"x6") may be acceptable at this ISO. The strange thing about ISO 800 is that it has in more details than the ISO 720 shot, it is also a 10 megapixels image. This shows how much noise-reduction is applied in High-ISO mode. ISO 3200 is both low in details and moderately high in noise. Expect this ISO to be of very limited use.

Nikon Coolpix L100