family blog, digital pictures

In traditional film photography of the past, the film you used was based on the ISO setting, also sometimes called the ASA. When purchasing film, you typically asked for a roll of ISO 64, or 100 or 200. The ISO is a measure of the film's sensitivity to light. The lower the ISO number, the less sensitive the film is to light. The higher the ISO number, the more sensitive the film is to light.

In practical terms what this meant was that when you were in low light conditions, such as indoors at a family event, you would want a higher ISO film; maybe a 200 or 400.  Of course you could use the flash, but there are some instances when even the flash won't help such as at a sporting event in a large arena or an outdoor night scene.  Another characteristic of the film is that an ISO 100 film is considered slower. This means the shutter of the camera must remain open longer to expose the film. A higher ISO film can have the shutter open for just a fraction of the time to capture the same image. Great, you ask, what does all this ancient history about film have to do with modern digital cameras?

Digital cameras also have an ISO setting. However instead of being set each time you change the film, you can change the ISO setting for each picture. The ISO setting you select, or the one the camera auto selects for you can make a big difference in the quality of your image. In the old days of film, a higher ISO film would produce a grainy shot. Imagine the pixels on your laptop were spread farther apart. Instead of being tightly packed as they are normally, there is a slight distance from one to the next, not much, maybe a few microns. How would your image look?  Not as sharp and crisp and the colors would not be as rich and saturated. This is how film grain looks. The higher the ISO, the further apart are the 'pixels' that make up the shot.

Digital cameras have their own version of grain called digital noise. Generally the higher the ISO you select, the more digital noise you will get too. Although digital noise is generally an unwanted characteristic of a digital photo, you can use it as a creative design element. This may be something you want for some artistic shots, but probably not for the typical head shots of your family.

So the best thing to do is to check the ISO setting of your digital camera. If it is auto selected, make sure in low light conditions you select the setting you want and let the flash (and a tripod) compensate for the poor lighting. That way your photos will look great no matter what the conditions.