Depth of Field

In creating your picture, you want to be able to control the focus of your objects.
For instance, when you are taking a portrait, you want to focus of the face of the person and not be distracted by the background. A close up of a flower is nice when the background is blurred, so as not to distract from the detail of the flower.


Taken with aperture f4.5 with a wide angle lens.

When taking a landscape shot you want your background in sharp focus, as in the following picture:


Taken with aperture f10 with a telephoto lens.

The setting you want to focus on is Aperture. When you first learn about aperture, it can be confusing. The smaller the number you choose on your aperture setting the bigger the opening of the lens, and the bigger the number you choose the smaller the opening.
This is the trick I use to remember how to choose aperture setting:
The closer the object is that I want to focus on, the lower the number is that I will choose. The farther away the object is that I want to focus on, the bigger the number is that I will choose.
Practice on your camera using the Aperture priority setting, usually labeled A on the camera. Take picture at various setting and see what you get.
Depending on the kind of lens you have, your aperture may be greater or lesser for the desired effect. We will discuss lenses in another lesson. For now practice in aperture Priority and see what works for your camera.