Which thermal for which job
- Monoculars: handheld scanners for finding warm animals, and for most hunters the first thermal to buy.
- Binoculars: two eyepieces for long sits, with less eye fatigue. Guide's TN and DN binoculars carry rangefinders, and the TN650M and DN70M add a 4K night vision channel.
- Clip-ons: they mount ahead of a day scope you already own.
- Riflescopes: they replace your day optic, with or without a built-in rangefinder.
The specs that matter
Sensor resolution, in the 256, 384 or 400, and 640 classes, sets the detail you can see and how far you can zoom before the image breaks up. NETD, in millikelvins, decides how the image holds up in fog, rain and humidity, and lower is better. The detection range on the box is the least useful number, because it measures where a heat blob appears, not where you can tell what it is.
Frequently Asked Questions
Thermal or night vision?
Thermal finds the animal by its heat, in total darkness and in light fog. Digital night vision shows a natural scene, which makes it easier to tell what the animal is.
What refresh rate do I need?
50 Hz keeps a running animal smooth instead of a stuttering smear, and every Guide thermal monocular we carry runs at 50 Hz.
Is a 384-class sensor good enough?
For close-to-medium range, under about 200 yards, yes, especially with good NETD. Past 300 yards detail turns pixelated and similar-sized animals get hard to tell apart.
For the specs in depth, read Thermal Imaging Specs Explained, and for binocular picks, Best Thermal Binoculars in 2026.