In this comparative test, we compared two mid-range thermal monoculars from different manufacturers, Pulsar Axion 2 XQ35 and Hikmicro Falcon FH25. Both devices can be classified as mid-range thermal devices, both in terms of technical specifications and price. At first glance, they differ in many technical characteristics, but if we understand the principle of thermal imaging, we will quickly realize that they are actually quite similar.
The price of both devices is also very similar, which presents an additional challenge for the customers. They must decide between two almost equally priced devices, on a bases of a lot of technical data, which must be properly interpreted and put into the context of the buyer’s needs and desires.
When listing all technical specifications, the most important factor is always the quality of the image displayed on the screen under various conditions, how reliably the device operates, how durable the batteries are, whether the device is compact and convenient, waterproof, and made of high-quality materials. Only in this way can we make the right decision to which manufacturer should we pay our hard-earned money. While we can compare technical specifications behind a computer screen, a credible answer to other questions listed above can only be obtained through a longer test of both devices together in real-life conditions of use.
What are the differences between Axion 2 XQ35 and Falcon FH25?
Focal length
The most obvious and commonly used characteristic in comparing thermal imaging devices is the focal length of the lens. The Axion has a 35mm focal length lens, which is considerably more than the Falcon’s 25mm focal length. Usually, a 10mm difference in focal length means a significant advantage, but only for devices that have the same other parameters.
Distance between pixels and NETD
The distance between pixels on the thermal sensor is 17 microns (µm) for the Axion and 12 µm for the Falcon.
The factory nominal value of NETD, which tells us how small thermal differences in the environment the sensor can detect, is less than 40 mK for the Axion and less than 20 mK for the Falcon.
Screen
The Axion’s screen is an AMOLED type with a size of 640×400 pixels, while the Falcon’s is much larger but only an OLED type with a size of 1024×768 pixels.
The two devices have the ability to capture images and videos with sound, but they differ in the resolution of their capture. Axion stores video and image recordings in a resolution of 528×400 pixels, while Falcon stores them in a resolution of 720×576 pixels.
Battery type
The Axion is powered by an APS5 battery with a capacity of 4900 mAh, while the Falcon uses a standard and easily available 18650 battery. When purchased, the Falcon comes with two 3200mAh batteries.
Design
The devices also differ significantly in shape and external dimensions. Despite the larger lens, the Axion is much more compact. It can be easily stored in a pocket of a hunting jacket, while the Falcon must be carried hanging around the neck.
Common Features
Both models have a housing made of magnesium alloys, which gives a sense of reliability and durability. The size of the thermal sensor is 384×288 pixels, and the lens is made of Germanium featuring a very fast f1.0 aperture.
How did we choose the devices for comparison?
Given that the devices differ in many more features than they have in common, someone might wonder if they are even comparable to each other. In thermal imaging devices, image quality depends on certain technical rules that cannot be avoided. Therefore, a lens with a longer focal length, a sensor with a smaller distance between pixels, a lower NETD value, and a faster aperture with a lower f-value will always produce a more detailed image.
However, we must realize that these factors are interrelated and complement each other. Understanding how a change in one of these factors affects the image helps us understand that devices with quite different technical characteristics can still be comparable.
In our case, Falcon has a lens focal length of 25 mm and a sensor with a distance between pixels of 12 µm, while Axion has a lens focal length of 35 mm and a sensor with a distance of 17 µm between pixels. If we divide the pixel size by the lens focal length, we get the MRAD value, under which the sensor covers the observed object.
- Falcon: 12/25=0.48 mrad
- Axion: 17/35=0.48 mrad
At a distance of 100 m, both devices cover a surface of 48 mm with 1 pixel of the sensor. The size of the sensors on both devices is the same, 384×288 pixels.
The combination of data about the angle of the observed object and the size of the sensor determines the field of view and the basic optical magnification. In both devices, both data are almost the same, as Falcon has 18.4 m field of view, while Axion has 18.6 m field of view at a distance of 100m. The basic optical magnification of Axion is 2x, while Falcon’s is 2.17x.
The technical data are therefore very similar, and the prices of both devices on the Slovenian market are almost the same.
We can easily say that the devices are completely comparable. However, values of NETD, manufacturer’s algorithms for image processing and display, size and quality of the screen, device dimensions, user interface, convenience of use, batteries, quality of workmanship, etc. are features that are supposed to make a difference between the devices.
Table of Specifications of Axion 2 XQ35 and Falcon FH25
| Specifications | Axion 2 XQ35 | Falcon FH25 |
|---|---|---|
| Sensor | 384×288 pix. 17 µm NETD <40 mK | 384×288 pix. 12 µm NETD <20 mK |
| Lens | F35/1.0 | F25/1.0 |
| Magnification | 2x basic optical (2x,4x in 8x digital zoom) | 2,17x basic optical (2x,4x in 8x digital zoom) |
| Field of view | 18.6 m/100 m | 18.4 m/100 m |
| Detection range | 1300 | 1200 |
| Display | AMOLED 640×400 | OLED 1024×768 |
| Power supply | APS 5 Li-ion Battery Pack Operating time 11 hours USB-C | 18650 Li-ion Operating time 7 hours USB-C |
| Dimensions | 152x50x74 mm 300 g | 190.3×58.3×65.2 mm 500 g |
| Video/photo recording | Resolution: 528×400 pix. Format: mp4 / .jpg 16 GB internal memory | Resolution: 720×576 pix. Format: mp4 / .jpg 64 GB internal memory |
How we tested
We have recently compared the Axion 2 XQ35 in several tests, and we can say that we got to know it very well. At the beginning, we were in a situation where we would compare one thermal imaging device that we know well against another that was completely unknown to us. Such a comparison, in our opinion, would not be appropriate, so we first took only the Falcon to the hunting ground and fully familiarized ourselves with its ergonomics, functions, and tried various settings. After about two weeks, we assessed that we also know the Falcon well enough and started comparing both devices in real-world conditions.
Since we were comparing devices from two different manufacturers, we always chose the device settings that gave us the best picture at the time. We did not limit ourselves to selecting the same levels of a certain parameter (contrast, brightness, signal processing, different filters…) on both devices. Only the colour mode was always set the same on both devices (usually to black hot mode).
As usually, we focused our comparison on using of thermal monocular during reduced visibility or in complete darkness.
We compared the devices based on:
- quality of manufacture and convenience of use
- image quality in different weather conditions
- width of the field of view and optical magnification
- usefulness in different hunting situations
- battery life
- quality-to-price ratio
Where we tested
The comparative test took place in a lowland hunting ground, where the highest density of game is represented by roe deer, hare, and foxes, with occasional sightings of jackals and wild boars. As a result, most of comparative observations were made on roe deer and hare. Very often also on foxes and occasionally on other living creatures that are active at night.
When we tested
Given the winter season, we mostly tested in excellent conditions for thermal vision, where the contrast between the cold environment and the warm bodies of living organisms was great. We also tried to capture moments when the weather conditions for thermal vision were poor, as this would allow us to more credibly evaluate which device has better heat detection capabilities.
During the testing period, we only managed to capture a slightly foggy atmosphere a few times, and we tested twice in heavy snowfall, where the conditions did not allow the use of digital night vision devices beyond 50 meters.
Testing thermal imaging devices in bad weather conditions is important because, unlike digital night vision devices, they are still very useful in foggy and humid air. The quality of the image and the detection range also decrease in foggy conditions for thermal imaging devices, but the degree of that depends on their technical capabilities and manufacturing quality.
Throughout the testing, we had always both devices with us and tried to observe different situations in the field simultaneously or one after the other.
Results of comparison
Quality of manufacture and convenience of use
Protection level
In the Axion series, Pulsar truly demonstrated the quality of its manufacture and the use of high-quality materials. The use of magnesium alloys gives devices a feeling of quality, robustness, and reliability. The protection level to external effects is in the IPX-7 standard, which means that the device should be able to withstand 30 minutes in water at a depth of 1m without consequences. Regardless of the manufacturer’s pledges, we have waived testing this technical specification and will take Pulsar’s word for it.
We cannot fault the quality of the Hikmicro Falcon either. Similar materials are used, and the final product looks very high in quality and robust. Moreover, the Falcon’s protection level to external effects is in the IPX-67 range, which means that, in addition to the same resistance to possible immersion in water at a depth of 1 m, the device is also resistant to dust and other microscopic particles.
Compactness of the device
Axion boasts exceptional compactness and can easily be stored in the pocket of a hunting jacket. In addition to the device, there is still room for winter gloves in the pocket of a regular hunting jacket. In contrast, the Falcon is a considerably larger device. During testing, I usually wore it around my neck because it was four centimetres longer and just over one centimetre wider than the Axion. Especially due to its greater length, it is not suitable for carrying in a pocket.
Carrying a thermal imaging monocular around your neck is not a problem when it serves as the primary or even the only observation tool. However, more problems arise when we also have a traditional hunting binocular with us, and let’s face it, the latter is still an indispensable companion for most hunters in the vast majority of cases.
When wearing both the thermal monocular and standard binocular around the neck at the same time, they often collide with one another, which increases the chances of damaging both devices. So, during the testing period, we left the standard binoculars at home. In cases when we were not hunting exclusively at night, we had to use a rifle scope for daytime observation, which is not always a good, let alone safe solution.
The slightly larger body of the Falcon also has its good side. It allows for a very good and firm grip of the device, which is particularly useful when observing a distant object – it is necessary to stabilize the device well. Even when using a support on a hard surface, such as the edge of a hunting hide, we will be able to stabilize the wide body of the Falcon more easily than the narrow and slightly taller Axion.
Control buttons
The arrangement of control buttons on the devices is very similar. Four buttons arranged in a straight row have approximately the same functions, but the commands on individual buttons are arranged slightly differently. This is not a problem in any case, as the user quickly gets used to the logical arrangement of individual commands in both cases.
However, we have noticed two differences that affect the use of the buttons. The buttons on the Falcon are less protruding from the body of the device than on the Axion and are therefore harder to recognize by touch. When touching them with bare fingers, this does not come into play as much, but when using gloves, especially thick winter gloves, it is very difficult to determine which button is under the finger by touch.
The user thus spends more time searching for the right button, often unintentionally pressing one of the unwanted ones. This is related to the second observed feature of the Falcon buttons. They are quite sensitive and the user often inadvertently activates a command. Starting video recording, digital zooming, or changing the colour palette were the most common consequences of unintentional pressure on one of the buttons. The worst thing that can happen during this is unintentionally pressing the on/off button for more than 2 seconds. This starts a countdown of three seconds to turn off the device, which cannot be stopped from that moment on.
Lens cover and focusing
The devices have a different lens cover. The Axion cover with a magnet and the possibility of attaching it to the side of a leather strap for is already well-known and works nicely.
The Falcon has a cover holder on the lens that can be adjusted by rotating it 360 degrees to position the open cover where we want it. However, the cover holder rotates very easily, and since it is positioned directly in front of the focusing ring, it often rotates when we adjust the focus.
The cover is released from the holder with a small catch, and at the beginning of use, we had a few instances where the entire cover holder came off the device when attempting to open the cover. However, nothing was damaged, and we simply reattached the holder to the device’s lens. With a little practice, we quickly got used to opening the lens cover smoothly.
Focusing at different distances in both devices is done through the lens ring. The ring is easier to reach and wider on the Axion. The Falcon’s ring is flush with the device’s body, and we needed a little more practice for quick focusing.
Design
The Axion’s body is rectangular in shape, and because a leather strap for holding is attached to one side, it is very easy to grip the device correctly and lift it to the eye. On the other hand, the Falcon is oval in shape, and it is very difficult to tell if we have picked up the device correctly at night.
During testing, we helped ourselves by always setting the lens cover on the right side of the device, so we knew how we were holding it by touch. The only problem was the cover holder, which, as previously described, tended to rotate and move the cover to a different position. To be fair, this is not very disturbing since we can still see the image on the screen, and when in a hurry, it is not essential whether the icons on the screen are upside down. The important thing is that we see the observed object, and if we have time, we can adjust and align the device’s position later.
In this part of the comparison, we can see that Hikmicro still lags behind Pulsar in some minor details. It is evident that Pulsar has been in the civilian thermal imaging device market for much longer than Hikmicro, giving them more experience in finding those fine final solutions that make their devices much more sophisticated and premium. At the same time, it is essential to emphasize that none of the observed differences significantly affected the usability of the Falcon, except, of course, for the differences in external dimensions, which significantly limit how Falcon is carried compared to Axion.
Image quality in different weather conditions
This part of the testing caused the most headaches and doubts when trying to assess which of the two devices performed better. The images displayed by both devices are undoubtedly very different, but it would be wrong to say that one is worse than the other.
Image quality on shorter distances
The difference in the displayed image almost certainly derives from a different combination of sensor and lens. Falcon’s 12µm sensor and NETD of <20 mK draws a very detailed picture of the observed object. Especially at close distances, the target image is noticeably more detailed, with very accurately drawn temperature differences. The obstacles (branches, bushes, grass) in front of the target are clearly visible, especially if they are in close proximity to the target. The background of the target is somewhat less detailed when observed from a higher position (hunting stand). At that point, the environment around the target becomes an indeterminate, patchy background.
The picture in Axion is also very good and detailed, but on shorter distances it cannot compare with Falcon. The difference in details diminishes with increasing distance, but remains visible.
The obstacles in front of the target are clearly visible, and the background of the target is somewhat better, in most cases displaying the shapes of the ground and ground vegetation.
Image quality on medium distances
The ability of Falcon to display very detailed temperature differences of the observed object reflected in an interesting and unexpected negative paradox when observing objects at medium distances. Due to the high sensitivity of the device, the image of the observed object is not fully displayed in the color mode we have selected in the settings (such as black in black hot), but white spots are visible inside the black-coloured target, showing parts of the body cooler than the other parts.
This gives us a very detailed depiction of the target, which partially blends with the background that is also depicted in a patchy image of different warm objects. Meanwhile, Axion colours the warmest body in the field of view uniformly black, making it stand out significantly against the background. This phenomenon is most evident at medium distances of 50 m–150 m, where the target covers only a small part of the field of view, but is still close enough for Falcon to distinguish temperature differences on the target itself and consequently draw it “patchy“. The image of a rabbit in a field taken at around 70m nicely illustrates this phenomenon.
Image quality in a heavy snowstorm
As mentioned at the beginning, the dry winter weather did not allow us to test the devices in truly challenging thermal imaging conditions (high humidity, dense fog, rain showers …). In fact, we were only able to conduct a roughly relevant test during a heavy snowstorm. In such conditions, the Falcon performed better.
Given the significantly better NETD value of the Falcon, this result should not surprise us, as NETD is the key indicator that plays a major role in a thermal imaging device’s ability to see through difficult thermal imaging conditions. However, it is necessary to be very cautious with the NETD values provided by manufacturers. There are no true industrial standards for measuring the NETD values of thermal imaging devices, and each manufacturer provides them based more or less on their own judgment. This is of course in line with their desire to advertise their product, and NETD has recently become one of the most commercially exploited features of thermal imaging.
Despite the limited conditions for comparing devices in poor weather conditions, it is necessary to emphasize the following. In all previous comparative tests, the Axion XQ35 has performed extremely well in bad weather conditions, and the fact that we saw further and better with the Falcon in dense snowfall during our test suggests that the NETD value <20 mK listed for the Falcon is probably close to the actual value and not just the result of marketing tendencies.
Three-step signal amplification function
In poor weather conditions, the usefulness of the three-step signal amplification function is proven to be very useful in Axion. The function can be set in three different stages, with the first stage being included when turned on and intended for favourable weather conditions. We recommend using the second and third stages of signal amplification when there is fog and high humidity in the atmosphere. The result is best observed by first observing the surroundings at the lowest setting and then increasing the level of signal amplification. A setting that works well in the fog may slightly degrade the image in good weather conditions, so we recommend that you check which setting works best for you in the given conditions when you start using the device.
Falcon does not have similar settings, but it has the option to turn on/off the image pro mode, which we left on all the time after initial setup, as in our opinion, it gave a slightly sharper image.
Depth of field
We were also somewhat surprised by the relatively small depth of field in Falcon’s image. This required us to rotate the image focusing ring more often. Image becomes out of focus quickly, just with slight changes in the distance to the observed object. The focusing range of Falcon is so wide that by turning the focusing ring all the way to one side, we can completely blur a part of the image to the point that it does not even show a living being that may be very close or very far away. Axion has a greater depth of field, and even if we turn the focusing ring to the end in one or the other direction, the image of a living being will still be visible on the screen, although completely out of focus.
It is very difficult to decide which device displays a better-quality image. At short distances, Falcon displays more details. However, at medium distances, this advantage decreases significantly and the so-called “Falcon masking” paradox appears. At long distances, both devices display warm objects as coloured patches or dots, without significant details, but Falcon allows for a slightly better detection of shapes, resulting in easier identification of the object at longer distances. The image from Falcon is generally slightly sharper and causes slightly more reduction in naked-eye vision during the night, while the image from Axion is somehow softer and more pleasant to the eye.
The width of the field of view and optical magnification
As we have already described in the chapter on choosing testing devices, the combination of a lens with a focal length of 25mm and a pixel pitch of 12 µm, and a lens with a focal length of 35mm and a pixel pitch of 17 µm, resulted in virtually the same field of view and base optical magnification on both devices (keeping in mind that both feature the same sensor resolution).
Usefulness in different hunting situations
We tested the devices at:
- a wild boar feeding site,
- while hunting from a hide in open fields and
- while stalking in the forest during day and night.
Feeding site
The biggest differences were observed when using the devices at the feeding site. Falcon’s ability to display details was a great advantage, as it allowed us to more accurately determine the gender, age, appearance, etc. of the animals in front of us.
Hunting from a hide
In hunting from a hide, the differences between the devices were already smaller. Apart from situations where the animal was somehow masked in the background due to the already described paradox at medium distances, Falcon still displayed the observed targets somewhat more accurately, and therefore allowed for identification at longer distances. Only at very long distances (over 300 m), all differences in details disappeared, and the target was displayed equally on both devices.
Stalking in daylight
When using the devices during stalking in daylight, we detected living beings in a similar way. Falcon showed trees and bushes in front of the target in more detail. However, the small depth of field of Falcon was quite noticeable. Obstacles that were very close to the observer were almost completely blurred if we wanted to have a sharp image of the target. The greater depth of field of Axion allowed us to have a good overview of the surroundings without constantly rotating the focus ring.
Comparing usefulness of the devices for different types of hunting, we can say that the winner, with a very small advantage, is Falcon.
Battery life
The two devices use different types of batteries. The APS5 battery in the XQ35 model has a capacity of 4900 mAh, while the Falcon comes with two 18650 button-top batteries with a capacity of 3200 mAh. We simulated the battery consumption and endurance in actual conditions.
The ambient temperature ranged from -50 C to +50 C on average. Besides observing, we frequently used the recording function and occasionally connected the devices to a smartphone. Upon arrival at the hunting ground, we turned on both devices and left them on the entire time without using the standby function.
Battery life on Axion 2 XQ35
It turned out that the XQ35 model can be used on at least two hunting trips without needing to be recharged. These trips typically lasted around four hours each. In between the hunting trips, we also used the XQ35 model for shorter, approximately 30-minute area patrols or evening walks with dog, but we never completely drained the battery.
Battery life on Falcon FH25
With the Falcon, we could use each battery without worry for one hunting trip and all the shorter walks in between. If we didn’t have a spare battery, we would definitely recharge it before the next longer hunt, but that wasn’t necessary. Since we get two batteries in the kit, we always waited for one to completely drain and then quickly replaced it with a new one in a matter of seconds. We practiced this process several times at home and soon became completely confident, so we also changed the battery at night in the hide, without using a flashlight. Therefore, the total operating time of both batteries included with the Falcon is longer than the operating time of one APS5 battery in the Axion. Even more importantly, the Falcon is powered by commercially available 18650 batteries which are widely available and affordable.
Some manufacturers of night vision and thermal imaging equipment (such as PARD) have always relied on this type of battery. In the best-case scenario, we power our shooting devices with the same type of battery as the monocular, which simplifies logistics for us.
We tested the Falcon with unprotected 18650 batteries without a button-top also. Despite the strong shaking, this slightly shorter battery did not lose contact with the +/- poles, and the device operated without problems. Therefore, from the perspective of battery endurance and convenience of using 18650 batteries, the Falcon is the undisputed winner. However, we dare to say that with normal use during hunting, we do not need spare batteries for the Axion XQ35. The user will likely quickly adapt to how much charge the battery needs to last the typical hunting time.
Ratio between quality and price
All the tests and comparisons that we have presented must now be crystallized in this key question for the customer – which model to choose, given that the price is almost the same. Given the small differences in quality of manufacture, device shape, and practicality for handling, we looked for the answer in the two most noticeable differences:
- The way the captured image is displayed and
- the significantly greater compactness of Axion.
If you intend to use the thermal imaging monocular primarily at night, preferably waiting for wild boars at a feeding ground, and the slightly larger size of Falcon does not bother you, then the choice is clear. Choose Falcon and take advantage of a more detailed picture with better capabilities of displaying important differences between live beings in front of you.
However, if you are looking for a thermal imaging monocular that will accompany you on all hikes in the hunting ground and you usually carry a lot of other equipment with you, the compactness of Axion is definitely a decisive factor that will allow you to have a thermal imaging device with you no matter what equipment your hunting style requires. For the super-compact Axion, there will always be some space.
It is important to emphasize that despite some differences compared to Falcon, Axion XQ35 provides top-notch image quality, rivaling even pricier and substantially larger thermal imaging devices.
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