Controlling depth of field via your aperture
A simple rule of physics means that when a small aperture such as f/22 is selected rather than a large aperture like f/2.8, the image will have more depth of field.
So, if you want to blur the background, select a large aperture and if you want to keep it sharp, choose a small one.
The middle ground, say f/8, is useful when there are a few objects that you want to keep sharp, but you want to avoid the background being very sharp.
Although it may be possible to close a lens’s aperture down as small as f/32 or even f/45, this isn’t usually advisable.
At very small apertures a phenomenon known as diffraction has a significant impact and actually makes images softer – even at the focus point.
- For more on this, see our guide to Annoying problems at common aperture settings (and how to solve them)
For this reason professional landscape photographers don’t tend to use their lens’s smallest aperture setting and instead open up by a stop or so.
PAGE 1: What is depth of field?
PAGE 2: Controlling depth of field via your aperture
PAGE 3: Controlling DoF by focal length
PAGE 4: Subject distance and depth of field
PAGE 5: Using all three factors to control DoF