I have noticed that noise increases with increasing ISO. How is it actually caused?
Ramesh Pai, Ahmedabad, via email
ISO stands for International Organisation of Standardisation. It indicates how sensitive the sensor or film is to the light present. The higher the ISO number, the lesser the light needed to make the exposure. In digital cameras, the image sensor has only one level of sensitivity.
At this sensitivity, the noise or errors are suppressed and are not visible. As you increase the ISO, the signal originating from the sensor is amplified and processed along with all its problems, including its noise.Tags: better photography, Question of the Day, Noise, exposure, SENSOR, ISO, January, International Organisation of Standardisation