ISO (International Organization for Standardization)
What is ISO? Not really an acronym; instead, the name derives from the greek word iso, which means equal. Founded in 1946, ISO is an international organization composed of standards from over 75 different countries. ISO in in a film camera is called "film speed".
In other words: ISO is the level of sensitivity of your camera to available light.
In other words: ISO is the level of sensitivity of your camera to available light.
- The lower the ISO number, the less sensitive it is to the light, while a higher ISO number increases the sensitivity of your camera.
- The component within your camera that can change sensitivity is called “image sensor” or simply “sensor”. It is the most important (and most expensive) part of a camera and it is responsible for gathering light and transforming it into an image.
- With increased sensitivity, your camera sensor can capture images in low-light environments without having to use a flash. But higher sensitivity comes at an expense – it adds grain or “noise” to the pictures.
Here is an example of what your ISO setting can do to a photo - The difference is clear – the image on the right hand side at ISO 3200 has a lot more noise in it than the one on the left at ISO 200. (“Noise” is the commonly-used term to describe visual distortion. It looks similar to grain found in film photographs, but can also look like splotches of discoloration when it’s really bad, and can ruin a photograph.)
Typically, ISO numbers start from 100-200 (Base ISO) and increment in value in geometric progression (power of two). So, the ISO sequence is: 100, 200, 400, 800, 1600, 3200, 6400 and etc.
- The important thing to understand, is that each step between the numbers effectively doubles the receptiveness of the sensor. What does it mean when a sensor is sixteen times more sensitive to light? It means that it needs sixteen times less time to capture an image!
Now that you know the basics of APERTURE, SHUTTER SPEED and ISO, click on the button below to combine your knowledge: