Extremely wide apertures (such as f/1.2 or f/1.4) are more rarely used, because at these apertures the depth of field is very shallow, which makes focusing more difficult and slows down autofocus. The main distinction is between outdoor sports and indoor sports – in outdoor sports the distances are greater and the light brighter, while in indoor sports the distances are lesser and the light dimmer. Accordingly, outdoor sports tend to have longer focal length long focus lenses with slower apertures, while indoor sports tend to have shorter lenses with faster apertures.