How a laser rangefinder works
A pulse of light, timed there and back.
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Time of flight
A photonics reference explains that a laser rangefinder sends a short laser pulse and measures its round-trip time. Since light travels at a known speed, the device works out the distance from half the round trip.
A second method
The same source describes a phase shift method, which works out distance from the shift in a modulated laser beam.
What limits range
The source lists challenges for long distances, including beam spread and weak return signals.
Laser safety
The source discusses laser safety and the use of eye-safe lasers in some rangefinders. Read the laser safety label and the manual for yours, and never point it at anyone.
Sources: RP Photonics Encyclopedia, Laser Rangefinders. Hunting Accessories is not affiliated with RP Photonics.
FAQ
General information only. Hunting laws, seasons, licenses, and hunter orange rules are set by each state; check your state wildlife agency's current regulations before you hunt, and take the hunter education course your state offers. If you hunt from a tree stand, wear a full-body fall arrest harness system every time you leave the ground, including while climbing up and down, follow the Treestand Manufacturers Association's Treestand Safety Guidelines and the maker's instructions, and have a plan for rescue. Tell someone where you will be and when you will return. In an emergency, call 911.
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