What in the world is ISO? Well, to simply answer that question, ISO means sensitivity. The lower the sensitivity, the finer the grain, but more light is needed. This kind of photography would be prefect for outdoor photography. Although, for indoor, low-light, or action photography (where fast shutter speeds are needed), more sensitive or "fast" film is used which is more "grainy".

Just like film, digital photography also has ISO, which indicates the sensitivity to light. Normally the standard setting for ISO on digital cameras is set at 100, although some cameras can go as low as 50. Sensitivity on digital cameras can also go as high as 200 to 800 or even 3,200 on high-end digital SLR’s. When increasing the ISO, the output of the sensor is amplified, so less light is needed. And unlike conventional film cameras which require a change of film roll or the use of multiple bodies, digital cameras allow you to instantly and conveniently change the sensitivity depending on the circumstances.

So next time you’re thinking of shooting indoors, outdoors, or even action photos, try adjusting and monitoring the ISO. Understanding sensitivity will help avoid over and under-exposed pictures.