Setting the ISO
The ISO (International Organization for Standardization) setting controls the sensitivity of the camera’s sensor to light. The ISO measurement was created so that the sensitivity of film to light would be standard across all film types. This standardization has transferred over to digital cameras, which means that ISO 400 on one camera is the same on any other. The higher the ISO setting, the more sensitive the sensor is to light. This is done by amplifying the signal from the sensor. The more you amplify the signal the more digital noise is introduced in your image.
Digital noise occurs at higher ISO settings. It gives images a grainy appearance with random, unwanted color flecks, especially in darker areas of the image.
The Nikon D3200 has an impressive ISO range of ISO 100 to ISO 6400. It can even be pushed a step higher to ISO Hi-1, which is the equivalent of ISO 12800. The ISO is adjusted in full stops, giving you the following choices: 100, 200, 400, 800, 1600, 3200, 6400, and Hi-1. Each time you change the ISO, you either double or halve the sensitivity to light.
Even though the camera has a Hi-1 setting, the results when using it are not optimal. It should only be used as a last resort.
You can set the ISO in three places: The Information display, the Shooting menu (), and the programmable Fn button (). The easiest way is to use the Fn button ...