Almost every week in our digital camera mini-classes, I get to a part of the class where everyone universally has a quizzical look on their faces, as if to say, "why did they do that?" And that's when I get to the portion of the use of ISO speeds on digital cameras. The letters ISO (or ASA for old-timers) on your digital camera settings refer to the equivalent of film speed on a older film based camera. ISO settings determines how sensitive the image sensor is to light, so the camera manufacturers have transferred the principle to digital cameras (At this point, our students take a collective sigh of relief!). The same principle applies; the lower the ISO, the sharper the image will be & the higher the ISO, the better it is in lower light & subjects that are moving. The higher ISO setting will result in a image that is not as sharp as one taken will a lower ISO & will show what was once known as "grain", but now is called "noise". Digital cameras will set the ISO automatically when in the "auto" setting, but can be changed in the "Program" or other settings on your camera to customize it to your particular shooting situation. You can also use the various mode settings that are common on most digital cameras such as action/sports, night portrait,etc. New digital cameras have the ability of shooting in extremely high ISO's, speeds that were unimaginable just a few years ago. And this breakthrough will truly enhance the overall ability for new cameras to take a better image. An excellent article on Gizmodo explains how " ISO is the New Megapixel" & that megapixel count should not be the only criteria in determining image quality on a digital camera: http://gizmodo.com/5470334/giz-explains-why-iso-is-the-new-megapixel Next up is the burning question:" I accidently erased all the images on my memory card! Is there any hope of getting them back?"