Thermal optics have been gaining popularity amongst hunters and outdoor enthusiasts over the last decade. Advancements in thermal imaging technology have brought the costs down to a more affordable level. You can still find thermal scopes with a five-figure price tag, but ATN has a wide range of options from $999 – $4,799. Pricing is largely determined by which thermal sensor and lens options you go with. You can select the optic that best suits your needs and typical hunting situations.
For the past 18 months, I’ve been using the ATN (Thermal Optic, Rifle) ThOR 4 640 2.5-25X which was sent to me for this review. I was a bit skeptical at how the ThOR 4 was going to perform after reading mixed reviews online about other ATN digital scopes. My attitude immediately changed after getting it in hand and looking through it for the first time. I haven’t had a completely trouble-free user experience. But overall, the reliability of the ThOR 4 during my use has been almost perfect.
The ThOR 4 uses ATN’s latest 4th gen Obsidian Dual Core 640×480 thermal sensor with a 60Hz refresh rate and a 1280×720 HD display. The result is a super crisp thermal image with a claimed detection range of 1,950 yds. With regular use and practice, it’s easy to identify deer and coyotes out to 400 yards. The 60Hz refresh rates means you can scan and shoot targets on the go and the image will remain smooth with no shuttering or lag.
Nothing compares to hunting at night with a thermal scope. Being able to detect and spot animals in complete darkness presents a lot more opportunities than using traditional night vision or spotlighting setups. It’s also just as useful during the day at detecting heat signatures behind brush or cover that you wouldn’t normally be able to see. The ThOR 4 640×480 delivers highly detailed images comparable to those twice it’s price, with better battery life and way more features.
Sensor: Obsidian IV Dual Core 4th Gen 640×480 (<25 mK)
Field of View: 12.5×9.7 degrees
Display Resolution: 1280×720 HD Display
Eye Relief: 90 mm
Tube Size: 30mm (Standard Rings Included)
Battery Life: 16+ hours
Weight: 2.2 lb
Warranty: 3 years
HD Photo and Video Recording 1280×960 @ 60 fps with Sound
Recoil Activated Video
WiFi Streaming and Controls through Obisidian App (Android and iOS)
Multiple Color Palettes & Reticle Options
SD Card Slot – Supports up to 64 Gb.
In the box you’ll find an assortment of accessories to immediately get started – scope rings, charging cable, soft zipper case, and a rubberized eyeshade cup. At the front of the scope is a focus ring for adjusting the thermal image itself. It’s easy to manipulate and feels smooth. I haven’t had any issues with the focus ring moving under recoil. The eyepiece also has a focus ring for the reticle and menu options. On the left side of the scope is a circular scroll wheel used for zooming, zeroing, and selecting menu options. The right side has the USB-C charging port, and MicroSD slot which are both covered with rubber flaps.
A control pad sits on top of the scope featuring 4 easy to use buttons. They are clearly marked and labeled with quick functions. Click the center OK button to access the scope menus. Although there are a lot of menu options, they are easy to navigate and understand. I would highly recommend spending at least 30 minutes playing with the menu screens just to familiarize yourself with how it operates. I primarily use the settings menu to access the thermal sensitivity, color palette, contrast settings, and display brightness. You’ll also find multiple reticle options. I prefer the traditional crosshair setup in red. Once you set your reticle and color, the other menu options are for specific situations or pairing with other ATN devices.
I charged the scope overnight before mounting to my rifle. Oddly enough, there is no charging indicator light or status screen that pops up when charging. The only way to know it’s charging is turning on the scope and seeing the lightning bolt charging symbol in the upper right-hand corner. It’s safe to say if you charge it overnight, you’ll be good to go. Using the supplied mounts, I got the scope leveled and installed on my hog gun. I’m running a Hardened Arms 7.62×39 upper and a Spikes Tactical lower. The factory mounts are not the best and I highly recommend replacing them with a sturdier set. During my testing, one of the screws stripped out of the factory supplied mounts.
At the range, you have the option of setting up shooting profiles for different guns or different loads. You can have up to 6 different profiles. Zeroing the ThOR 4 is simple using ATN’s “one shot zero.” But first you need to make sure you’re using either a specialized thermal target or use an object that will show a heat signature – like hand warmers, cold water bottles, or even foil tape. Without this, you won’t have an aiming point on the paper target. Pick your aiming point and fire a few shots. Verify with your spotting scope or binos to where they’re impacting. Head to the zeroing function in the scope menu. Use the top directional buttons to move the reticle to where the bullet group is. Save your settings and now the gun is zeroed. It’s simple and fast if you’re on paper to begin with. I have had a frustrating afternoon or two chasing down impacts when switching from the 7.62×39 to 5.56.
The ThOR 4 has held zero well until the rear scope ring screw stripped. I noticed a zero shift and found the screw was loose and somehow stripped out. Since changing mounts I haven’t had problems with zero shift.
The next weekend I packed up for the ranch to stretch out the ThOR 4 and see what it could really do. Located in the Texas hill country, the land is covered with thick brush making it difficult to hunt at night without thermal optics. While the ThOR 4 has several color palettes to choose from, I typically stick with white hot or black hot options. If you want to go predator mode, that’s available too. Eye relief is generous and I only use the rubber eyepiece when using it unmounted.
Sitting on the south hill looking north towards the other side of the property is 1,410 yds. The ThOR 4 was able to see the entire hillside with extreme detail, but I didn’t see any heat signatures. We then moved to the north side, now looking south towards our previous position, and placed a buggy at the halfway point. Once on top of the hill looking south, the buggy was easily identifiable at 700 yards. I could also identify 3 deer. Two were standing at around 875 yards and the third was up the south hill approximately 1,000 yards out. The image below is at 10x magnification. One thing to note about thermal zoom, at this point its just digital zoom and not optical. The image quality severely degrades as you zoom in.
Moving about the property we went to different feeders searching for hogs. The entire time I leave the ThOR 4 on and you can occasionally here the shutter refreshing the thermal image. The power button also doubles as a refresh in case you need it on the fly. I do have the standby set to come on after 15 minutes of inactivity.
Looking at the feeders its easy to see how much protein or corn remains. It beats having to lower the feeder or banging on the side to check the levels. Just another benefit of having a thermal. You can also spot mice jumping around at 100 yards.
One of the guys at the ranch has what many consider to be the gold standard of thermals – a Trijicon Reap-IR 35mm. This was also the first thermal I hunted with, and the picture is superb. However, both of us agreed the ThOR 4 produces an image on par with the nearly 2x as expensive Reap-IR.
Let’s be clear, I’m not directly comparing these units. Putting them side by side the picture is not all that different and certainly not twice as good as the price would indicate. They serve two totally different purposes and are in two different classes. The Reap-IR is built to get you through a warzone. The ThOR 4 wasn’t intended for that.
I’ve had the chance to use the ThOR4 throughout multiple seasons and conditions. The image quality degrades slightly during extremely humid conditions or the pouring rain but detecting heat and hunting are still doable. The image just gets slightly grainy but adjusting the contrast and thermal sensitivity settings can help with that. The clip below was recoil activated video, shooting a hog at 110 yards during a 90-degree humid summer evening at 10x magnification:
After using the ThOR 4 for nearly 2 years, I can say that the scope reliability has been almost perfect. Last December, I was out hog hunting in east Texas during some of the coldest temperatures of the year. It was sleeting and 28 degrees outside. The image froze, so I power cycled the unit. When it powered back on, the image still wasn’t coming through clear then it froze again. I packed up early that night and returned home the next morning. Back at my desk the ThOR 4 was operating normally again so I decided to check on the firmware status and noticed an update was available. Since the update, I’ve used it in below freezing temps without problems.
The advertised battery life I’ve found to be accurate. The longest I’ve been hunting was 12 hours during a 2-night hunt and I still had battery remaining. I’ve let the ThOR 4 sit for as long as 2 months without using it and the battery holds a charge well. It’s great being able to leave the scope turned on during the entire hunt. You can also use the USB-C connector to hook up any external battery bank to power the ThOR 4 in a pinch.
Overall, I have no complaints with the build quality and performance of the ThOR 4 640. The 2.5x base magnification has a bit too narrow field of view for my preference and hunting setup. I would prefer the 1-10x ThOR 4 640 for its wider field of view. The 2.5x lens makes scanning and panning in the UTV challenging. A thermal monocular would be ideal for scanning on the move and then use the ThOR 4 for a closer look. The 2.5-25x lens would be best suited for wide open plains or scanning across ridgelines.
Build quality of the scope itself is great. I’ve had no problems riding around with it for hours holstered in the UTV. It has taken a spill or two and the scope was unharmed. The body seems to be well sealed and has seen multiple rainy nights. There is a slight bit of surface rust that formed on one of the rearward facing screws. A quick scrub with a q-tip dipped in CorrosionX took care of that.
The provided scope mounts are good enough to get you going, but need to be replaced for long term use. I stripped one of my screws and they are not very durable in general.
The mobile application hasn’t worked well for me. I tried using the Obsidian app on my Galaxy S9 but it was one of the glitchiest apps I’ve ever used. Every time you would try to import a photo from the gallery the app would freeze, and you’d have to power cycle the scope. The remote viewing feature would occasionally work, and it was fun to be able to see what the shooter is looking at on your mobile device. Now I just download them from the microSD card. The recoil activated video is reliable if you remember to enable it in the menu and hit the record button.
Some features on the ThOR 4 I’ve never even used like the ballistic calculator and weather functions. I’m sure they are great for those who need them, but I’m rarely shooting anything outside of 150 yards at night. The app and additional cludgy features aren’t necessarily deal-breakers for me. I’d buy the scope for its thermal performance and how well it holds zero. Not the mobile app or ballistic calculator. At $4,299, the ThOR 4 offers more standard features and performance than others in its price range making it one of the best valued thermal scopes available.
Outside of hunting, I’ve used the ThOR 4 to help detect air leaks around my house during winter and it helped me locate a burst pipe during the winter freeze. There are several miles of bayou surrounding my house where I’ll often walk with the thermal allowing me to spot owls and other birds at night. Scouting and tracking is much easier with a thermal. One big downside to using a thermal, it kills your natural night vision. Which doesn’t really matter to me since I can locate anything with the thermal and use a spotlight if I want to see it better with the naked eye.
I’m sad to finally return the ThOR 4 after such a long time. It’s proven to be a useful tool in the field and at home; it’s just plain fun to have. My nighttime hunting success has easily doubled. If I wasn’t finding hogs, it was rabbits or other varmints. There was always something to see! Yes, there are a few gimmicky features, but the ThOR 4 gives users Godlike abilities to reveal what wants to be hidden.