So far we have talked about Aperture and shooting in Aperture Priority mode.
We’ve talked about shutter speed and shooting in shutter speed priority mode.
There is a third way to control light with your camera and that is ISO. ISO, in digital photography, is how sensitive your camera’s sensor is to light. The lower your ISO is the less sensitive your sensor is. The higher the ISO the mores sensitive it is. Higher ISO settings are generally used in low lighting situations to give you the ability to increase your shutter speed.
The standard ISO setting is 100 and at a low ISO you get very little noise or grain in your photographs-they look crisp and clean. But as you increase your ISO you will get increased amounts of grain. Take a look at this low light picture. It was shot at a ISO of 3200 in very low light (the only light was coming from the computer to the left of the shot). The high ISO resulted in significant noise.
Noise is not necessarily bad and many photographers will actually bump up their ISO to get a grainy affect in artistic shots. I actually like nighttime black and whites shot at a high ISO. I think the grain and noise add to the moodiness of the image.
While I typically try to keep my ISO at 400 or below when I am taking pictures of the boys, having the ability to adjust ISO in order to use a desired shutter speed and aperture has allowed me to capture moments that I otherwise would not have been able to especially during these winter months when natural light is at a premium.
Get ready, because next week we’re going to put it all together and take the leap to shooting in manual.