Lesson 43 of 100
Understanding focal length
No prior knowledge needed. Keep your camera or phone beside you and try each control or idea as it appears. The aim is understanding, not memorising terminology.
Focal length and field of view
Focal length is written in millimetres. On the same camera, a shorter focal length normally gives a wider field of view and a longer focal length gives a narrower one. Sensor size affects the field of view a given focal length produces.
Zooming is not moving
Changing focal length changes how much of the scene fits in the frame. Moving the camera changes the relative apparent size and spacing of near and far objects. This is why two similarly framed photographs can have very different perspective.
Compatibility matters
For interchangeable-lens cameras, the mount must be compatible with the camera. Do not buy a lens because its focal length sounds right without checking the exact mount and any sensor-format limitations.