ANSI FL1 throw

What it means

ANSI/NEMA FL1 is the US flashlight standard, approved in 2009. Its “beam distance” is the distance at which the light’s peak intensity falls to 0.25 lux, roughly the light of a full moon. It is not measured in the field. It is worked out from the candela:

Beam distance (meters) = √(candela ÷ 0.25) = 2 × √candela

So 100,000 cd gives about 632 m (692 yd), and 400,000 cd gives about 1,265 m (1,383 yd). Doubling the distance takes four times the candela.

What it changes in the field

FL1 throw is a fair way to compare beams from different lights, because every maker who follows it uses the same threshold. It is not how far you will identify an animal. Full moonlight on a coyote at the edge of the beam is dim, and humidity, dust, your scope and your eyes all cut the useful distance. One maker that uses FL1, Sniper Hog Lights, tells buyers to expect to identify at about one half to two thirds of the FL1 distance.

Hunting-light makers often quote other distances instead: “target illumination”, “eyes at” (eye shine), “identification” or IR range through a named night vision unit. Those are the maker’s own field claims, measured however the maker chose, and they do not compare across brands.

What to look for

• A maker that publishes both candela and an FL1 distance, so you can check one against the other.
• FL1 figures for each color. Red LEDs usually throw much shorter than green or white in the same light.

How we use it on this site

Where a maker publishes candela, each light page shows the FL1 throw calculated from it, in yards with meters in parentheses, beside the maker’s own distance claim. Where a maker calls its distance FL1 but the distance does not follow from its own candela (more than 3% apart), we show both and say so. IR rows get no calculated throw: what you see with IR depends on the night vision unit.