In Digital Photography, ISO is used to measure the sensitivity of the image sensor and they are measured by numbers. All DSLR cameras should have the numbers 100, 200, 400, 800, 1600 and 3200. These are the most common ones that most DSLR cameras would have. However, due to the still advancing technology, these numbers can reach a higher number in higher end cameras. Beginners in photography who uses DSLR cameras would most likely put the ISO setting in ‘Auto’ to allow the camera to set the ISO for them. However, is low lighting conditions, it would set a very high ISO and result in very grainy pictures. This would result in a lower quality picture taken by the camera.
When choosing your ISO, make sure that you understand the other three aspects of DSLR photography which are Aperture and Shutter Speed. To get that clear picture, make sure to take note of the surroundings and subject, to ensure the correct settings for your camera.