Depth of Field (DOF) camera guide
Controlling the depth of field (DOF), or how much of your shot is in focus, is simple enough, and can have a real impact on your photos.
Chances are not everything in your picture will be the same distance from the camera. In some cases you want as much of the photo in focus as possible (when shooting a group of people for instance), but in other cases you can help draw attention to the one subject in focus by having the rest of the background out of focus and therefore blurry (most commonly used in portraits). The following two photos demonstrate the difference. In both cases I focused the camera on the red car in front.
Maximizing each effect:
For a shallow depth of field:
To maximize the depth of field:
I've tried to make this as simple as possible -- but there are certainly other factors, and lots of math, involved in depth of field calculations. I found the following two pages useful: