What Is ISO In Digital Photography?

In a nutshell, there are three settings in a digital camera that are the most important for you to know. Aperture, ISO and Shutter Speed. In this blog I will break down the most important information of ISO and when to use it. In digital photography, ISO stands for the international standards organization. ISO measures the sensitivity of the image sensor in your digital camera.

ISO can be measured from 100 to past 12800 in some cameras. A low ISO number (100) means the less sensitive your camera is to light and the finer the grain. A low number allows you to shoot in normal light. A high ISO number (1800) means that your sensor becomes more sensitive to light. The higher you go the better your images will come out in low-light situations.

Maximum ISO us used before and after sunset to get the sharpest images. (ISO 1600)

ISO 800-1600 is primarily used inside of buildings, sunset (dusk) and even sunrise and early morning.

ISO 400 can be used in mid-morning and midafternoon.

ISO 100 or even 200 can be used in normal daylight (outdoors) to get maximum sharpness.

Take a look at this example.

On the far left you will notice that the low ISO number created a smoother photo with less grain compared to the far right images. This photo, as you can see, was taken during normal daylight. So the low ISO is what would have been needed in order to capture a better photo unlike a higher ISO.

Now that you know what ISO is and when to use it, check out the diagram below and use it as a cheat sheet for when you need it!