What Does ISO Stand For?

I was once in a large, well-known electronics store, when I couldn't help but overhear a conversation between a customer and a sales clerk. The customer had a compact digital camera in their hand, and asked the sales clerk, "What is ISO? Do I really need it?" The clerk, looking to seal the sale, said, "It's not really important. All cameras have it, but you will not use it." Well, I beg to differ.

So, just what does ISO stand for in photography? ISO stands for International Standards Organization, and it is a standardized industry scale for measuring sensitivity to light. This can be used in relation to how sensitive camera film is to light, but more commonly today, it pertains to the sensitivity of a digital image sensor. ISO is measured in numbers, with the lowest number being the least sensitive to light, (e.g. ISO 50 or 100), and the highest number being the most sensitive to light, (e.g. ISO 6400). Almost all digital cameras today allow you some control over your ISO settings, so it is important to know what it is, and what effect it has on your images.

ISO and Exposure