Camera mobiles - ISO Specifications

The important things that you should note while buying a camera mobile or any other camera is its ISO specifications. The ISO specifications determine the amount of light entering through the aperture. There has to be a fine balance with the amount of light entering your camera and the time for which your aperture should be open. If your aperture time is too high, the camera's sensitivity will be high and you can capture the darker images without much image noise. But high aperture time will reduce the image stabilization and also add to image noise. So there has to be some trade-off.

There are different levels of ISO and shutter speed. Nokia N95 uses 1/111 and ISO 200 whereas Sony Ericsson k850i uses 1/30 and ISO 64. The above images are taken with fixed shutter speed and aperture value. Bear in mind that the ISO and the shutter speed are the two elements that determine the amount of light that is to be captured, when you have a fixed aperture size. A slower shutter speed allows more light to reach to the matrix. A higher ISO makes the matrix more sensitive to the light that comes in. However it's a really fine balance between these two, since the higher the ISO is, the more noise there is on the image. The slower the shutter speed, the more likely you are to get a blurry picture due to camera shake. The camera software has to balance those two in the best possible way to avoid both blurring and noise. Sometimes one is taken care of at the expense of the other - it's up to the camera to decide, really.
The following explanations might help you in better understanding of this concept:

ISO 100:	Great for bright sunny days, at the beach or on the snow. Produces clean images that are great for enlargements.
ISO 200:	Great for overcast daylight pictures (noise levels may increase, but in most cases not noticeably)
ISO 400:	Great for lower lighting conditions (indoors, night time) or when you need to capture faster moving subjects in lower lighting conditions. In many consumer cameras, ISO 400 can make photos look very noisy in dark areas of the picture. The reason a higher speed ISO helps you capture fast moving subjects is because a higher ISO makes the image sensor of the camera more light sensitive. This forces the camera to use a higher shutter speed to compensate for the extra brightness, which in turn helps to "freeze" movement in the captured frame.

So depending upon your choice you can choose your camera or mobile with high or low ISO and shutter speed specifications.