What Does Focus Throw Mean?
Focus throw is measured in degrees and represents the amount of rotation needed to turn a lens’ focus ring from its MFD (minimum focus distance) to infinity. Â A manual focus lens tends to have a much larger focus than an autofocus lens because this allows a greater degree of accuracy. Â Cinema lenses, which are manual focus, all have very long focus throws so as to allow extremely precise focus.
In general, you’ll also find that lenses with a very wide maximum aperture also have a long focus throw. Â The wider the aperture, the shallower it is possible to make the depth of field and therefore the harder it is to focus correctly when the lens is wide open. Â A long focus throw means the relative change in focal distance per degree of focus ring rotation, is less. Â The same can be said for macro lenses as well, since this is a situation where photographers are also often working with very shallow depths of field.
Additional Reading
- What does MFD Mean?
- What Is A Cinema Lens?
Cinema lenses have a very long focus throw