Aperture and Depth-of-Field

Depth-of-field is the distance range that is in focus.
The aperture has a visible impact on your photos because the depth-of-field increases if the aperture gets smaller, i.e. the f-number bigger.
Click on the photo on the left for a bigger view of the examples.

Typical examples where you may want a certain depth-of-field are:

• Landscapes usually look better if they show a wide range from the foreground to the background in focus (→ choose small aperture = high f-number).
• For portraits a background out of focus is good to avoid distracting from the face (→ choose big aperture = small f-number).

Apart from the aperture the depth-of-field is also dependent on the focal length: Wide angle lenses (small focal length) have a bigger depth-of-field than tele lenses (bigger focal length).