For your information, ISO is the film speed (in human words film sensitivity to light) of the film or the sensitivity of the sensor in digital camera. It is one of the key elements in the exposure triangle. The higher the ISO number, the greater the film sensitivity (chemical sensitivity)/ the greater the digital sensor sensitivity to light and vice versa for a lower number of ISO.
The sensor or film sensitivity is very useful to have a good exposure setting as it wont add extra effect into your photo but only increase the brightness of your photo. Thus you can use a different combination of aperture and shutter speed while using ISO to compensate for the exposure. With the correct combination of ISO speed, aperture, and shutter speed you will be able to get a perfect image.
ISO measures the sensitivity of the image sensor recording light in numbers of 100, 200, 400, 800, 1600, 3200, and so on.
There are a few basic principles of ISO
- The smaller the number the less sensitive your camera is to light and your photo grain will be much finer.
- The bigger the number the more sensitive your camera is to light and your photo grain will be much rougher.
- ISO 100 is considered normal as you will have perfect crisp shots (very very little noise/ grain) but you won’t always be able to use it due to different lighting conditions.
- In dark conditions where light source is very little, you should use higher number of ISO settings so that you can increase you shutter speed. If your shutter speed is too low, you picture might be blur due to motion blur. The higher ISO can be used to compensate the exposure.
