ISO is your camera's sensor sensitivity to available light. The ISO setting on a DSLR or mirrorless camera controls this sensitivity. Along with APERTURE and SHUTTER SPEED, it makes up the exposure of any photograph.What Do ISO Numbers on My Camera Mean?The International Organization for Standardization gives ISO its standard values. Meaning that all manufacturers like Nikon, Canon & Sony comply with the same standardization.
In the days of film photography, depending on what film speed they bought, photographers were locked into what was then called the ASA standard. Film had sensitivity values of ASA 50, 100, 200, 400, 800 and 1600.
Today, with digital cameras, a photographer can easily toggle between different sensitivities to light. Now called ISO. Ranging from 50 and up. What Do the ISO Numbers on My Camera DO?With ISO, the sensitivity to light is doubling with each full stop.
Example: ISO 400 is two times more sensitive to light than ISO 200, and four times more sensitive to light than ISO 100
Most cameras will either allow you to choose ISO in one-stop, or third-stop increments.
Noise & GrainThe higher you raise your ISO, the more digital noise and grain you get in your image. So, for higher quality (clean) images, shoot with a lower ISO.Who Cares About This Noise Thing Anyway?Some street photographers intentionally shoot with a higher ISO for a grainy look that it gives a photo. The noise/grain from shooting with high ISO settings can give a digital photo a gritty look, or possibly old school film looks.Many photographers use "P-Mode" (Program Mode) while shooting photographs. Simply put, this means you are allowing the camera to choose the exposure settings for you. It does its very best job to choose an ISO, but sometimes this comes at a cost. A lot of ISO noise!
ISO And the Latest CamerasNew cameras are continuously pushing the limits of ISO. Higher and higher ISO values are possible without all the noise. Manufacturers are producing "smarter" cameras every year. Cameras are getting much better at choosing exposure settings for you, but still none of them come close to competing against a well-informed, skilled photographer, like yourself!
By John McLenaghan
ThemeSong Media - Orlando, FL