Focus Limiter
A switch that restricts a lens's focusing range, so autofocus does not search through distances the subject cannot occupy.
Measured in
m
In depth
A macro or telephoto lens takes a long time to rack from its minimum distance to infinity, and every failed search costs a picture. Limiting the range to, say, three metres to infinity means a missed lock recovers in a fraction of the time. It costs nothing when the subject genuinely stays within the chosen band.
Examples in practice
A 100 mm macro set to limit at 0.5 m to infinity focuses on a portrait subject far faster than with the full range enabled.