Burris · BTH35 v3

Estimated range, standing human, clear air

IdentifyRecognizeDetectBox claim

Burris BTH35 v3400×300 · 12 µm · 35 mm

112 m identify182 m recognize729 m detectbox says 1,000 m (deer)

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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.

Burris

Burris BTH35 v3

Handheld monocular400-class

The Burris BTH35 v3 is a 400×300, 12 µm thermal handheld monocular behind a 35 mm lens. On the Johnson yardstick that is an estimated 729 m detection and 182 m recognition range for a standing person; Burris quotes 1,000 m detection (deer). At 1.4× our estimate, its detection claim is the most conservative in the catalog.

Approx. price: ~$2,160
Sensor: 400×300 · 12 µm
Lens: 35 mm · 3.3×
Est. detection: 729 m · 797 yd

Best for

Scanning from a stand, a truck or a field edge

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Box claim vs. what the optics support

Manufacturer says

1,000 m

detection, deer

Johnson estimate

729 m

detect · 182 m recognize · 112 m identify

Claim ÷ estimate

1.4×

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

One pixel of this unit sees 0.343 mrad (12 µm ÷ 35 mm). Two pixels across a 0.5 m human is 0.5 ÷ (2 × 0.343) × 1000 = 729 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 burrisoptics.com page + BTH v3 manual (SKU 300636; 2x internal 18650).

Sensor: 400×300
Pixel pitch: 12 µm
NETD: ≤50 mK
Refresh rate: 50 Hz
Lens: 35 mm
Base magnification: 3.3×
Digital zoom: up to 4×
Field of view: 7.8° horizontal
Display: 1280x960 LCOS
Claimed detection: 1,000 m
Claim basis: deer
Run time: 5 h
Battery type: Internal Li-ion
Weight: 22 oz
Length: 9.8″
Laser rangefinder: No
Ballistic calculator: No
Records video: Yes
Wi-Fi: Yes
IP rating: waterproof (no IP code published)
Warranty: 3 years
Approx. price: ~$2,160

Derived here

IFOV: 0.343 mrad
Est. detection: 729 m
Est. recognition: 182 m
Est. identification: 112 m
Claim ÷ estimate: 1.4×
Derived field of view: 7.8°
Pixels per degree: 51

Features

400 sensor
12 µm
35 mm lens
50 Hz
Records video
Wi-Fi
waterproof (no IP code published)
LCOS 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

12 µm pitch — the 35 mm lens sees what a 17 µm core would need 50 mm to match
Records video and streams to a phone over Wi-Fi
Detection claim is only 1.4× our estimate — one of the more conservative box figures here

Against it