F-stops.

Two major factors in photography are F-stops and shutter speed. The F-stop refers to the opening that admits light into the camera body, called the aperture. The higher the F-stop, the smaller the opening. You can use the aperture setting to determine how much of your photo is in focus, called depth of field. If you're taking a picture of a large scene, and you want things in the foreground to be in focus as well as things in the background, you would use a high F-stop (a smaller aperture setting) to ensure a large depth of field. If you're taking a portrait you would use a low F-stop (a wider aperture setting) to reduce the depth of field and this would result in just the person's face being in focus with the background blurred.

The F-stop and the shutter speed work inversely with each other. With a wide aperture you need a slow shutter speed and vice versa. If these are not set correctly you will end up with a photo that is either overexposed or underexposed.

Some cameras have settings called Aperture Priority or Shutter Priority. This enables you to set the F-stop or the shutter speed to the setting you want and the camera will choose the correct shutter speed or F-stop for you. This gives you really great shots without really having to know what you're doing. It's fantastic!

Now, for homework I want you all to go out and take one picture with a large depth of field, and one with a very short depth of field. Turn them in to me by the letter H and yes, this will be on the quiz.