The hottest segment of the electro-optics market is thermals. Thermal weapon sights. Thermal viewers. And thermal clip-ons, which transform a daylight rifle scope into a night-hunting device.
By allowing us to detect hogs, coyotes, and other predators at night, they’re literally giving hunters extra time as they give us the ability to see in the dark.
But consider the average price of a serious thermal is $3,500. You can pay as much as $8,000 for the top-performing consumer models. That’s an expensive bar to enter for most would-be night hunters.
Happily, you can get into the thermal market for under $1,000, but there are important features and capabilities that you simply won’t get for that price point.
Still, getting into the thermal market with a capable short-range device that has enough talents to help you succeed at night hunting without breaking your budget can let you know if this particular category of optics is right for you. And for deeper investment in a higher-priced, more capable thermal.
Here are some considerations as you shop for an entry-level thermal, and then some specific brands and models worth your attention.
UNDERSTANDING THERMAL RESOLUTION
The most important specifications for every thermal is the resolution of its thermal sensor, expressed in microbolometers, and the resolution of its display, expressed in pixels.
The sensor is the high-tech circuitry that translates the temperature variations registered by the germanium objective lens to visible images. The very best consumer-grade sensors have 1280x1024-microbolometer sensors. The industry standard is a 640x512-microbolometer sensor. And many of the budget-priced thermals use either a 256x182- or 400x300-microbolometer sensor.
The higher the number, the more detail, depth, and distance you’ll see in the night. Lower-resolution sensors tend to deliver smudgy, indistinct images and have reduced useful ranges. One rule of thumb: you can expect to pay about double for every doubling of sensor resolution. This thermal core is one reason the devices cost so much, and why the most powerful thermals cost even more.
Just as with digital cameras and even our smartphones, the display resolution is an indication of how rich and vibrant the image that reaches our eyes will be.
The best displays have 1024x768-pixel displays, but some of the top thermals have high-definition 2560x2560-pixel displays.
Generally, you want a display that’s at least as resolved as the sensor, and ideally the display should have more than 640x480-pixel resolution.
Any less, and you’re going to get a harsh, two-dimensional view of the night world. The most resolved displays, those high-definition screens, deliver bright, clear, almost 3D views of the night and its contents.
The other dimension to note is the objective lens size, expressed in millimeters.
Just like with traditional optics, the larger the objective lens, the bigger and brighter the image. But the objective lenses in thermals is made with a rare-earth mineral called germanium, and it’s expensive, so the larger the lens, the more you’ll pay.
The best have 60mm lenses, but you can get into a very good thermal with a 35mm or even 25mm lens.
UNDERSTANDING THERMAL FEATURES
Most entry-level thermals should have these capabilities:
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Wi-Fi connection to a mobile app
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Ability to record photos and video
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A range of color palettes (standard is 5: white-hot, black-hot, red-hot, rainbow, sepia)
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Selectable reticles (if it’s a weapon sight)
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Stadiametric rangefinder (this is a ranging system that uses the relative size of known animals to determine their distance)
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Objective lens focus control
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At least 4-hour run time on either rechargeable or non-rechargeable batteries
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Digital zoom
Some of these attributes are more important than others, and some are superfluous.
For instance, many thermals have a feature called picture-in-picture mode that magnifies the aiming point. That’s great if you’ll be doing longer-range shooting, but for most shots inside 100 yards it’s not necessary.
Same with hot-spot tracking, a feature that follows the hottest-temperature portion of the image. It can be great for following an animal but it can also be distracting.
For my uses, I want a Wi-Fi-enabled thermal that will easily transmit the media (photos and video) that the device records to an app on my phone where I can easily share it or save it for later.
And I want a variety of palettes that I can use in changing situations. I spend 90 percent of my time on white-hot but it’s nice to have options for especially bright or busy environments. And, for weapon-mounted thermals, I want an easy method for zeroing the device.
THERMAL OPERATING SYSTEM
One of the most overlooked attributes of thermals is how easy they are to use in the field.
It’s one thing to learn a complicated series of buttons and their functions in the comfort of your home. But in the field, where it’s often cold, sometimes muddy, and always dark, you want to select a system that’s simple, fast, and intuitive. The best of the bunch are single-button operations, with a rotary dial that enables menu navigation and selection.
Useful alternatives are three-button systems. And some devices allow users to customize buttons in any way they want.
I like units that have a single button for recording either video or photos, and maybe a single button for rangefinding.
PRICE
With thermals, just like with traditional daylight optics, the old adage “you get what you pay for” is mostly true. The best of the bunch are downright expensive, but their performance usually justifies the price. But there are some very good price-point thermals that may not have all the attributes of the spendy units but will get you in the night-hunting game.
As you consider the price, also consider the warranty. Most companies have limited-term warranties on their electronic products, and thermals are nothing if not specialized electronics.
A 5-year warranty is a very good value, since you should know after a season or two if some aspect of the device is going to crap out or not.
Some brands have 10-year warranties, which is worth paying for. And others — Sig Sauer comes to mind — have lifetime warranties, which is a great testament to the durability of their gear and an attribute that’s worth a higher price than a device from another brand with identical attributes but a shorter-duration warranty.
UNITS TO CONSIDER
Here are thermals, in each of the three categories (sight, viewer, clip-on) that are worth a look if you’re just getting into the market, or if you’re interested in upgrading a budget-level device.
Priced at well under $600, this is one of the best bargains in the thermal market, and is fully capable of getting you on coyotes and pigs out to near 200 yards. It will easily capture video and photos and transmit them to your phone. It comes with a solid rail mount. It’s easy to operate. And it gives hunters an opportunity to dip their toe in the thermal category without taking out a second mortgage.
It achieves that accessible price with its low-powered 256-microbolometer sensor. Because of the low wattage images are smudgy and low-resolution. But it makes up for an underwhelming image with a single-button/rotary-dial operating system that’s fast and intuitive. The scope has 10 selectable reticles, five based on MOA and five based on MIL dimensions adjustments, and seven color palettes. While the Athlon doesn’t exactly have a ballistic calculator, it does have the ability to customize reticles to various holdover values at specific distances.
The quick-detach rail mount is a nice add, and the 8-inch-long compact form factor makes this a great AR carbine sight. If you want a bit more resolution, consider Athlon’s Cronus ATS Pro 35P-400, with a 400x300-pixel core.
Nocpix SLIM H35
For just a little over $3,000, you get both a very capable hand-held viewer and a carbine-sized weapon sight that’s optimized for mid-distance hunting.
This dual-use unit is the answer to those hunters who recognize that, in order to be in the hog- and predator-hunting game, you need both a thermal viewer and a thermal scope. But who has the budget to afford both? This single unit might not be the ideal of either platform, but it’s good enough at both that budget-minded hunters should seriously consider it.
In field testing, I managed to transition from a hand-held monocular to slapping the unit on a rifle rail and making a 200-yard shot inside 30 seconds. The mounting is assisted by a smart magnetic tab that snaps onto the rail and doesn’t move the zero an appreciable amount. Experienced users could probably make this function swap in half that amount of time.
Another hybrid, this compact red-dot and thermal reflex sight is a little big for handguns, but it’s perfect for home-defense shotguns, pistol-cartridge carbines, and all manner of close-range platforms. Priced at under $2,000, it’s not going to shine as a predator or even hog-hunting thermal, but it’s not intended to.
The DRS-TH can run in separate red-dot and thermal modes, or in dual-use mode where users can dim down the 2 MOA red dot to a barely visible aiming point and use the thermal for low-light target detection and recognition. It’s a fast and effective combination. It has a 1x base mag but magnification steps to 3x and 5x, and has either 65 or 32MOA aiming circles. Display options include white hot, black hot, outline, and highlight modes. It lacks a Bluetooth or Wi-Fi transmitter, so on-board media has to be transferred via USB cable.
Guide TE211M
This fun, useful, somewhat frivolous thermal viewer, priced right around $500, splits the difference between a toy and a serious hunting tool. On the fun side, it’s one of the most affordable and user-friendly thermal devices you’ll find, employing a touch screen similar to your smartphone to easily navigate operation at night or when time is of the essence.
On the serious side, the image it delivers will benefit every hunter, whether you’re trying not to bump deer as you leave an evening bow stand, need to see what’s outside your tent (or house) at night, or want to scan a landscape out of curiosity or necessity.
The compact, pocket-sized form factor allows it to go everywhere, and the decent 256x192-pixel thermal core is powerful enough to identify targets out to about 250 yards. But the tiny
10mm germanium objective lens limits the resolution the thermal core can render to the human eye. In addition, the fixed focus limits useful sharpness to about 100 yards. But it boasts a 10-year warranty, 6-hour run time, and 16GB on-board image storage. At 111mm, about 30mm shorter than the length of your iPhone, the Guide fits in any pocket and goes anywhere. Serious fun.
Guide TE 421
Slightly bigger brother to the Guide TE211M, the TE 421 is slight larger and has more thermal-imaging horsepower. It’s compact enough to fit in a pocket, stupid-simple to use, and versatile enough for close-in surveillance and mid-range target ID, it has all the features of units costing three to four times its price.
Those features include image focusing on the objective lens bell, diopter eyepiece focus, seven color palettes, Wi-Fi connectivity to a very good mobile app for image sharing and live-streaming, and smart attributes like single-button/rotary menu navigation, battery-saver mode, refresh countdown clock, picture-in-picture and hot-track modes, and a claimed 1,400-yard detection range. Not bad for a handy thermal that costs under $1,000 and features an impressive 10-year warranty.
Topdon TS004
This flashlight-looking monocular is really intended for household use, finding heat leaks in windows and hot fuses in breaker-boxes. But it’s a very handy unit to keep in a car’s glovebox or in a hunting pack to help you see what goes bump in the night no matter where you are.
The under $400, the unit is limited by its fixed focus; objects beyond about 100 yards are simply fuzzy warm blobs. It doesn’t have Wi-Fi or a companion mobile app. It stores up to 32GB of photos and videos on its onboard memory, but to transfer them to a phone or computer, you must connect a USB cable. The unit has a 1-year warranty, half of the industry standard, and the tiny 13mm objective lens further throttles its performance.
But the Topdon is affordable and a relatively risk-free way to see if thermals are for you.
Like the Nocpix SLIM mentioned above, Sig’s ECHO CV25 is a dual-use marvel, serving both as a clip-on paired with a daylight slave scope or as a stand-alone thermal sight. That versatility helps explain why a $4,500 thermal is listed as an entry-level unit, but because of its talents at both tasks, plus its lifetime warranty, it’s simply a solid investment and a very solid build in its metallic housing.
The little 25mm CV25 packs a ton of features in its 5-inch-long frame. They include navigation buttons that can be customized, recoil-activated recording, and a very good 640-class thermal sensor. The rail-mounted ECHO SV25 is a perfect match for an AR platform. The unit doesn’t have a rangefinder, but it pairs nicely to Sig’s BDX app and integrated-device ecosystem.
Nocpix QUEST H35R Thermal Binocular
This full-featured thermal binocular packs a great image inside a chassis that looks, and behaves, much like a traditional daylight binocular. Priced right at $3,000, it has a useful digital and optical zoom, a simple 4-button navigation, and all the image capture and wireless transmission that you’d expect in a high-end viewer. But its greatest value proposition, besides its ultra-high-def display and 1,000-yard laser rangefinder, is that it delivers all this in a form factor that’s easy to hold still and operate without pulling it off target or fussing with objective-lens focus controls.