InfiRay Finder FH35R product image

InfiRay Finder FH35R

The FINDER FH35R is a thermal monocular made by InfiRay and is part of the Finder II series.


The Finder FH35R comes equipped with a clear 35mm f/1 lens to capture thermal signatures. The FOV on this thermal monocular measures 12.6 x 10.1 degrees. It comes with a 4x digital zoom to get additional details.

Inside the housing of the Finder FH35R you'll find the (uncooled, 12µm) 640 by 512 pixel thermal sensor with a refresh rate of 50Hz. The NETD of this thermal monocular is <35mK.

The measurements of this thermal monocular are 160 x 90 x 50mm (l/w/h) and weighs 400g. This device is rated IP67. It's protected against dust, shocks and water (splashes). It handles temperatures between -20°C and 40°C.

The Finder FH35R is built for surveillance, hunting trips and law enforcement (police, border patrol etc.).



Lens35 mm
Optical zoom3.4 x
Digital zoom4 x
FOV (h/v)12.6 ° / 10.1 °
Thermal typeUncooled
Sensor resolution (h/v)640 pixels / 512 pixels
Pixel pitch12 µm
Sensitivity35 mK
Display resolution (h/v)1024 pixels / 768 pixels
Refresh rate50 Hz
Image polarityWhite hot, black hot, red hot, rainbow
Output screen colorFull color
Dimensions (l/w/h)160 mm / 90 mm / 50 mm
Weight400 g
TypeLi-ion battery pack
Number of batteries1
Battery life6 hours
Law enforcement
Search & rescue
Fire fighting
Operating temperature-20 °C / 40 °C
Environmental ratingIP67

DRI Ranges

DRI stands for Detection, Recognition and Identification and is based on the widely used Johnson's criteria.

  • Detection Detect if an object is present
  • Recognition See what type of object it is (i.e. person, vehicle, airplane)
  • Identification For example see if someone is a friend or foe
Detection Recognition Identification
Rabbit 525 meters 131 meters 65 meters
Person 1847 meters 461 meters 230 meters
Vehicle 4472 meters 1118 meters 559 meters

Please note that these values are calculated, always consult the manufacturer for official range numbers.


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