Advantage of high ISO setting - avoid camera shake in low lights.
There is a direct correlation between shutter speed and ISO settings. By increasing the ISO settings, the shutter speed increases proportionately, for example, from 1/15 sec at ISO 50, the shutter speed increases to 1/30 sec at ISO 100 and 1/250 sec at ISO 800. At these later speeds, you'll avoid camera shake and can freeze slow movements.
Unfortunately, there is a drawback to using high ISO settings as mentioned earlier amplifies electric signals which is applicable for background noise too which is present in camera's circuitry. This distorts the image signal and creates a speckled or noisy image.
General Rules and tips for ISO Settings:
- Use an ISO of 100 or 200 when taking photographs outside in sunny conditions.
- If the sky is overcast or it is evening time, then use an ISO within the range of 400 to 800.
- Night time or in cases of low light you might need to set your digital camera ISO to 1600.
- Use Tripod if taking photographs at low ISO settings in overcast / low light conditions.
How to reduce noise from the picture.
- Use camera which has got larger sensors because larger photosites found on such sensors collect light more effectively and thus don't need as much amplification to capture a poorly lit scene as a small sensor.
- Now there are lot of photo editors in market (Adobe, Photosuite, Picassa) which helps to remove noise.
Next I will discuss about interesting stuff : Shooting and Composition.