Lesson #4: ISO

ISO is the setting that controls how sensitive the sensor in your camera is to light. In the good ole’ days we called this film speed. Lower numbers mean the film is less sensitive, folks would refer to this as a slow speed film. Higher numbers mean that the film is more sensitive, or faster.

The problem with ISO is that as you increase it, image quality goes down. It’s barely noticeable with the current crop of DSLRs. But photogs using film always made it a priority to use the slowest film possible (unless they were trying for some special effect).

So for this assignment take your DSLR out a little before dusk. Set it to “P” mode and find a stationary subject. Start at your camera’s lowest ISO and take a photograph of your subject at each ISO your camera offers. Then go in and look at your photos and see what effects ISO has.

Next lesson!