Depth of field. What is it? What can I do with it?
Depth of field is essentially the "area in focus" of a shot. In the examples below you can see with a large depth of field everything is in focus but with a shallow depth of field you can pin point something in a shot and really bring it out from the rest.
I'm not going to explain why it happens because it's complicated and it's boring but essentially the main thing is the lower the F number the shallower the depth of field. At f11 and above pretty much everything will be in focus at f1.8 only a small amount of the shot will be in focus.
A couple of examples:A large depth of field
A shallow depth of field
What you need:* A camera which allows you to adjust the aperture.
The theory:Using Depth of Field (DoF) is mostly for artistic effect. Set your camera to aperture priority mode and chose the lowest f number you can go down to. This varies from lens to lens and even on where you have set the zoom to on a zoom lens. You are now set for a shallow DoF shot. Distance from subject and focal length also make a difference to the DoF. The closer you are to the subject the better and if you use the longest end of your lens that will also make the DoF shallower.
Focus on your subject and snap away! A good way to practice is to set up a shot in your house and the camera on the tripod. Then take 10 shots of exactly the same thing but start at the lowest F stop and work your way up. You'll really be able to see how it effects things. Once you've got the hang of controlling howe much DoF you want in a shot then you can really get creative.
Tips:* Shooting Landscape? Use an F stop of F8 all the way up to F22 as you want everything in focus normally.
* Doing a closeup? Time to get that narrow depth of field and really pick out what you want from the shot.
Nick