Review: InfiRay Outdoor Bolt TL35 V2 Optimized Thermal Riflescope

Today’s night vision technology is light years ahead of what was available only a few short years ago — allowing hunters to stretch their efforts into the darkest hours.

Review: InfiRay Outdoor Bolt TL35 V2 Optimized Thermal Riflescope

Night vision devices will be celebrating their 100th anniversary in 2029. The development quickly caught the attention of the armed forces and, despite its infancy, a few range-finding and targeting versions were issued to German tanks during World War II. Others found their way onto a handful of U.S. sniper rifles and other small arms. Those early thermal and infrared systems were slow making it to the commercial market, largely because of their expense and the military’s fruitless attempts at keeping the technology secret. Even today the average consumer can’t own the cutting-edge varieties that stand watch on the front line of freedom, but some of the models we can claim offer amazing performance.

The Bolt TL35 V2 optimized thermal riflescope from InfiRay Outdoor is among them, and it takes a route noticeably different from many of its contemporaries. Most obvious is a profile that emulates a traditional riflescope, complete with what resembles windage, elevation and parallax turrets in all the right places. Its ergonomic and digital controls are atop the scope — to the rear — close at hand and ambidextrous. The company kept users squarely in focus with this design. Dissecting the specifications proves that point.

Sensor — The Bolt TL35 V2 uses an InfiRay 12-micron Micro II thermal core, which has a resolution of 384x288 pixels. There are larger sensors (cores) available, although price tags usually go up exponentially. On average the higher the resolution the better, although there are enough variables at play that many smaller 320x240 pixel thermals routinely garner rave reviews from hunters. Pixel pitch — the distance between each pixel — for example, is critical to performance. On this InfiRay the measurement is 12 microns, about as tight as you’re likely to find commercially available today. Rendering drops dramatically when that distance increases, although there’s no shortage of successful 17-micron units on the market.  

There’s still no guarantee of performance with an expensive sensor with densely packed pixels. Slow refresh rates mean lag time — the predator displayed at the eyepiece could have changed position as you begin to squeeze the trigger. This one operates at 50 hertz — 50 times per second. To put that into perspective, most 4K HD movies are painfully slow 24 frames per second. All that raw data collected at the 35mm objective lens would be long numeric strings of ones and zeros without decoding, processing and, finally, transmission to the display. It’s here where subpar algorithms and processors routinely compromise usability in the field. 

 The Bolt TL35 V2 Bolt Optimized Thermal Rifle Scope has the profile of a traditional riflescope, with the only exception being a control pad atop and back toward the eyepiece. It handles field changes wisely within reach while behind a firearm and is designed for ambidextrous use.
The Bolt TL35 V2 Bolt Optimized Thermal Rifle Scope has the profile of a traditional riflescope, with the only exception being a control pad atop and back toward the eyepiece. It handles field changes wisely within reach while behind a firearm and is designed for ambidextrous use.

Processing and Display — The TL35 V2 uses the firm’s proprietary MATRIX III image processor and, judging by how it performed during testing, leaves little to be desired. In fact, calling it a pleasant surprise is an understatement. It keeps pace when panned moderately fast across the landscape.  

The display is crisp, contrasty and measures a very generous 1024x768. It’s also AMOLED (active-matrix organic light-emitting diode), a breakthrough that brought faster refresh rates and reduced power consumption to high-end electronics. It’s brightness adjustable and there are four different display styles — allowing hot items downrange to be white, black, red, highlighted or color graded. 

Game didn’t make its regularly scheduled appearance during my short loan period. Out of desperation I removed the optic from my rifle and resorted to my daughter’s sheep. Rousting them out of bed at night was a loud task, and I’m still hearing complaints. 

Photos, Video and Battery — That “glamor” photo session did uncover the optic suffers a malady common to night-vision scopes armed with a camera. The slow shutter speed meant the slightest move on my part, or my woolly models, resulted in image blur. I surmised the scope’s fixed aperture setting at 1.1 — wide open and enough to make expensive photo lenses jealous — would help, but roughly half the images I took fell victim. When things went right, though, the 1024x768 jpgs it produced were nice. Don’t expect stunning landscapes. It’s heat signature rendered, not striking autumn leaf color.   

The scope also takes video in the MP4 format. Leave the memory cards at home, because the scope ships with a 32GB internal storage drive — enough for 24 hours of video or roughly 20,000 images. When you’re ready to download, simply plug the USB C cable (supplied) into the unit, insert the other side into your computer and everything transfers as if the optic is a thumb drive. It worked flawlessly on my Windows 10 machine.

That USB slot on the scope, by the way, is the internal battery’s charging port. The TL35 V2 comes with a wall adapter for that purpose. An on-board LED reflects battery status — changing from red to green when fully charged. Internal battery life is advertised at eight+ hours, although mine gave me a warning on the display at about six. Admittedly I was pushing buttons like a Vegas junkie addicted to slots, though. The unit also has the option of adding an 18500 or 18650 battery (not included). With a dual battery supply runtime extends to more than 10 hours. 

Covers on the additional power supply compartment and USB port deserve special mention. Located where windage and parallax adjustments, respectively, traditionally are located, they thread on convincingly and are backed by O-rings to keep the elements at bay. Couple that with internal storage and its little wonder this electronic optic has earned an IP67 ingress rating. 

The optional battery storage compartment also uses brass, or a composite thereof, fittings. Some higher-performance members of the automotive industry do the same to take advantage of the metal’s resistance to that green “rust” that develops with battery leak. Smart choice.

An LED above the USB C charging point indicates battery condition during charging.
An LED above the USB C charging point indicates battery condition during charging.

Menu Access — Zeroing and toggling through the menu options is accomplished by depressing and/or rotating the knob that occupies the spot traditionally reserved for the elevation turret. Options include color palette, access to six different crosshairs, image sharpness and zeroing distance. Back toward the eyepiece, on top of the scope, is a control panel with four rubber-coated buttons. There you can turn on the unit, adjust brightness, change display and snap photos or videos (both on the same button, which is nice). 

A black bar atop the display allows heads-up monitoring of a variety of functions, including Bluetooth, Wi-Fi, battery status, compass reading, non-uniform conformity mode (which corrects pixel drift if needed) and more. It’s comfortably readable without being overly invasive in the field-of-view. It didn’t appear in the images taken during testing, either — an unexpected bonus. 

At the Objective — The Bolt TL35 V2 is manual focus and the ring for that duty, just behind the objective lens, has enough texturing and speed bumps for gloved use. Turning it on the test scope was stingy, although it’s bound to ease up with use. The scope also ships with a lens cover up front, and it’s critical to keep it on when not in use. Prolonged exposure to direct sunlight, as inadvertent as it might be, can degrade sensor performance. That 35mm objective is germanium, a material that allows heat to pass through unencumbered. Glass does a good job of blocking that thermal signature, on the other hand. 

Other Touches — The diopter focuses quickly and easily, and display was crisp and clear for even this enthusiast sentenced to a lifetime behind reading glasses. Included with the optic is a screw-on bellows to minimize scatter and detection by your quarry. Tube diameter is 30mm and it’s constructed from T-6061 aluminum. It’s built stout, measures 15.74 inches in length and tips the scale at 32.87 ounces. 

A pair of matching rings are shipped with the optic and Allen wrench, making it ready to go on a Picatinny out of the box. It comes with a five-year warrantee and rated to handle recoil from a 7mm Rem. Mag. or .300 Win. Mag. The scope comes with a pretty snazzy carry case, too. 

Sensitivity, Detection Range and Magnification — Thermal optic sensitivity is rated in millikelvins, a measure of heat. The lower the number, the better the performance. This one comes in at less than 50. In testing it worked extremely well. But there’s a cautionary note to consider. Manufacturers adhere to a standard that reflects the distance at which two pixels detect an object’s heat signature. The Bolt comes in at a sweet 1,750 yards, but don’t expect to identify an animal that far out based on a pair of adjacent points in the display.

Optical magnification runs up to a crystal-clear 3X. There’s an additional digital 4X available, allowing it to operate at 12-power. There it did a solid job of rendering the image, but pixelation increased proportionately with zoom. Within 100 yards, or longer, in total darkness this scope shines brightly anywhere between 6X and 1X. 

At the Firing Line — Zeroing was a breeze, but only after reading the manual. It and the one-shot-zero option are simple, but far from hunting-writer intuitive. Mounted to a Bergara chambered in .22-250 Rem. it held zero perfectly through multiple sessions and, unlike a few of its contemporaries, didn’t prove fatiguing after long periods — at least the black-and-white display option didn’t. I’m not so sure I’d want to spend hours behind the color-graded version.  

The controls are strategically located, and each provides those familiar inaudible “clicks” when depressed or rotated with bare hands. Feedback vanished with gloved use. It didn’t take long to get familiar with each of their locations and functions they perform, however, a decided bonus. 

The Bolt TL35 V2 Bolt optimized thermal riflescope packs more features than I’ll ever use. The long list includes Bluetooth capability, Wifi, the ability for multiple people to watch field-of-view over your shoulder — so to speak — on their smart devices and much more. There’s even the option of adding a Bluetooth ILR-1200-1RF rangefinder.  

This scope is a solid performer that would allow any predator hunter to extend his or her hunts into the darkness hours, without surrendering familiarity and performance. I’d have no reservations using it in foul weather. As a bonus it won’t draw Robo Cop comparisons at the range, so feel free to break it out on those sunny days.  


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