Leica · Calonox 2 Sight LRF

Estimated range, standing human, clear air

IdentifyRecognizeDetectBox claim

Leica Calonox 2 Sight LRF640×480 · 12 µm · 42 mm

135 m identify219 m recognize875 m detectbox says 2,210 m (1.7 m x 0.5 m subject, Leica 'acquisition' at 2 px (Leica 'detection' 770 m at 6 px))

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Estimated from pixel pitch and lens focal length using the Johnson criteria (2, 8 and 13 pixels across a 0.5 m human critical dimension), clear air, 50 % probability. A model of the optics, not a measurement — real range depends on temperature contrast, humidity and the animal.

Leica

Leica Calonox 2 Sight LRF

Clip-on640-classLaser rangefinder

The Leica Calonox 2 Sight LRF is a 640×480, 12 µm thermal clip-on behind a 42 mm lens, with a built-in laser rangefinder. On the Johnson yardstick that is an estimated 875 m detection and 219 m recognition range for a standing person; Leica quotes 2,210 m detection (1.7 m x 0.5 m subject, Leica 'acquisition' at 2 px (Leica 'detection' 770 m at 6 px)). It is the heaviest of the 10 clip-ons here, at 23.1 oz.

Approx. price: ~$5,899
Sensor: 640×480 · 12 µm
Lens: 42 mm · 1×
Est. detection: 875 m · 957 yd

Best for

Keeping your day scope and its zero while adding thermal at night

We may earn a commission. Price and availability on Leica’s site may differ.

Box claim vs. what the optics support

Manufacturer says

2,210 m

detection, 1.7 m x 0.5 m subject, Leica 'acquisition' at 2 px (Leica 'detection' 770 m at 6 px)

Johnson estimate

875 m

detect · 219 m recognize · 135 m identify

Claim ÷ estimate

2.5×

how much further the box reaches than a 2-pixel, 0.5 m criterion

One pixel of this unit sees 0.286 mrad (12 µm ÷ 42 mm). Two pixels across a 0.5 m human is 0.5 ÷ (2 × 0.286) × 1000 = 875 m. The box figure is usually computed against a person’s 1.8 m height instead, which is why it comes out higher. Full explanation.

Specifications

Manufacturer-published figures, cross-checked against leica-camera.com technical data PDF (May 2025), leicacamerausa.com (price; says made in Germany, while the Calonox 2 manual's CE block says Made in Portugal — origin left null).

Sensor: 640×480
Pixel pitch: 12 µm
Refresh rate: 60 Hz
Lens: 42 mm
Base magnification: 1×
Field of view: 10.3° horizontal
Display: 1920x1080 OLED
Claimed detection: 2,210 m
Claim basis: 1.7 m x 0.5 m subject, Leica 'acquisition' at 2 px (Leica 'detection' 770 m at 6 px)
Run time: 5 h
Battery type: Internal Li-ion
Weight: 23.1 oz
Length: 5.5″
Laser rangefinder: Yes
Ballistic calculator: No
Records video: Yes
Wi-Fi: Yes
IP rating: IP67
Warranty: 10 years (Passport Protection Plan)
Approx. price: ~$5,899

Derived here

IFOV: 0.286 mrad
Est. detection: 875 m
Est. recognition: 219 m
Est. identification: 135 m
Claim ÷ estimate: 2.5×
Derived field of view: 10.4°
Pixels per degree: 61.3

Features

640 sensor
12 µm
42 mm lens
60 Hz
LRF
Records video
Wi-Fi
IP67
OLED display

What the spec sheet says

Read from the published specifications and this catalog’s own numbers — not from owner reports, which we have not collected for this unit.

For it

640×480 core — 2.8× the pixels of a 384-class unit
12 µm pitch — the 42 mm lens sees what a 17 µm core would need 60 mm to match
60 Hz core — 20 % more frames than the 50 Hz norm when an animal runs
Built-in laser rangefinder
IP67 sealed — survives immersion, not just rain
Records video and streams to a phone over Wi-Fi
Detection claim is only 2.5× our estimate — one of the more conservative box figures here

Against it

NETD not published — sensitivity cannot be compared on paper
Internal battery only — no field swap, carry a power bank
23.1 oz — 1st-heaviest of the 10 clip-ons here
23.1 oz hanging in front of the day scope's objective
Rangefinder but no ballistic calculator — the holdover is still yours to work out
~$5,899 against a ~$3,799 median for clip-ons here