Armasight · Sidekick 640

Estimated range, standing human, clear air

IdentifyRecognizeDetectBox claim

Armasight Sidekick 640640×480 · 12 µm · 19 mm

61 m identify99 m recognize396 m detectbox says 709 m (human-sized target)

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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.

Armasight

Armasight Sidekick 640

Handheld monocular640-class

The Armasight Sidekick 640 is a 640×480, 12 µm thermal handheld monocular behind a 19 mm lens. On the Johnson yardstick that is an estimated 396 m detection and 99 m recognition range for a standing person; Armasight quotes 709 m detection (human-sized target). The box figure is 1.8× the Johnson estimate — a narrower gap than most of the 60 claims recorded here.

Approx. price: ~$3,299
Sensor: 640×480 · 12 µm
Lens: 19 mm · 1×
Est. detection: 396 m · 433 yd

Best for

Walk-and-scan glassing from a jacket pocket

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

Box claim vs. what the optics support

Manufacturer says

709 m

detection, human-sized target

Johnson estimate

396 m

detect · 99 m recognize · 61 m identify

Claim ÷ estimate

1.8×

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

One pixel of this unit sees 0.632 mrad (12 µm ÷ 19 mm). Two pixels across a 0.5 m human is 0.5 ÷ (2 × 0.632) × 1000 = 396 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 armasight.com.

Sensor: 640×480
Pixel pitch: 12 µm
NETD: <40 mK
Refresh rate: 60 Hz
Lens: 19 mm
Base magnification: 1×
Digital zoom: up to 4×
Field of view: 24.16° horizontal
Display: 1024x768 OLED
Claimed detection: 709 m
Claim basis: human-sized target
Run time: 1.5 h
Battery type: CR123
Weight: 9 oz
Length: 4.1″
Laser rangefinder: No
Ballistic calculator: No
Records video: Yes
Wi-Fi: No
IP rating: IP67
Warranty: 3 years
Country of origin: USA (assembled from U.S. and global components)
Approx. price: ~$3,299

Derived here

IFOV: 0.632 mrad
Est. detection: 396 m
Est. recognition: 99 m
Est. identification: 61 m
Claim ÷ estimate: 1.8×
Derived field of view: 22.9°
Pixels per degree: 28

Features

640 sensor
12 µm
19 mm lens
60 Hz
Removable battery
Records video
Under 20 oz
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 19 mm lens sees what a 17 µm core would need 27 mm to match
60 Hz core — 20 % more frames than the 50 Hz norm when an animal runs
Runs on CR123 cells you can swap in the field
9 oz — 3rd-lightest of the 18 handhelds here
IP67 sealed — survives immersion, not just rain
Detection claim is only 1.8× our estimate — one of the more conservative box figures here

Against it