Setting the correct ISO level on the digital camera

One of the settings that you can change in digital cameras is ISO setting. ISO number refers to the sensitivity of the camera’s sensor to  light. Most pocket cameras have a standard normal ISO of 100 and it can be raised up to 1600 or even more.  More the number, more sensitive the sensor becomes to light and so you can take pictures in low light too.

Why should I not always keep a high ISO becaasue pocket cameras tend to get low light in many situations?

Raising ISO leads to grainy  or noisy look of the photo. The colors, instead of transiting smoothly over different parts of the object, seem to have differentiated into ugly dark and light grains of different colors.  If you have an old pocket camera, chances are that the picture would be grainy even at ISO of 400 or 800; however, newer cameras use new technology that reduces noise over higher ISO settings.

But ISO is very useful in these situations:

• When there is dim light but you cannot use flash, e.g. in museums;
• When reducing shutter speed to get more light will lead to shake either because of shaking of the camera or movement of the object [and yet you cannot use flash];
• When the light is very dim and you need to use more than one techniques for getting maximum light. In such situations, you are often left with no choice: if you don't take picture with high ISO, you may be left with no picture at all.