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Steiner Nighthunter H35 GEN II Field Test

On our recent test in the hunting ground, we evaluated a thermal vision monocular bearing a resonant name in the field of hunting and shooting optics. However, the fact remains that thermal vision technology and traditional optical devices based on glass lenses share little in common.

Steiner Nighthunter H35 GEN II (Source: Steiner)
Steiner Nighthunter H35 GEN II (Source: Steiner)

Despite Steiner’s undeniably impressive products, it finds itself somewhat on the periphery in the realm of thermal vision devices, especially in the face of the dominance of Pulsar and certain Chinese manufacturers. The Nighthunter H35 GEN II model boasts highly promising technical specifications, and through extensive use in hunting, we assessed its competitiveness against more well-known brands and whether it lives up to its distinguished name.

Technical Specifications

The Nighthunter H35 GEN II thermal vision monocular is equipped with a sensor with a resolution of 640×512 pixels and a pixel pitch of 12 µm. The thermal sensitivity (NETD) of the sensor is currently not particularly exceptional (<35mK). The thermal sensor is complemented by a Germanium lens with a focal length of 35 mm and a fast F1.0 aperture. The image is displayed on an OLED HD screen with a resolution of 1280×960 pixels. The large screen nicely complements the otherwise very wide field of view, measuring 21.7m / 100m.

Steiner Nighthunter H35 Gen II Thermal testing

In terms of technical characteristics, the Steiner Nighthunter H35 GEN II falls into, what could be called, the entry-level into top-class thermal vision monoculars. Until recently, it was commonly believed that the top-quality class was represented by monoculars with sensors of resolutions 640×480 or 640×512 and lenses with a focal length of 50 mm. The pixel pitch of the sensors was 17 µm or 12 µm, and the NETD value ranged from <40 mK to <25 mK, with sensors of 17 µm generally achieving better thermal sensitivity. A typical representative of such a high-end monocular and a standard for comparing other products was the Pulsar Helion 2 XP50 PRO.

With the development of sensors, those with 12 µm were achieving increasingly higher sensitivities, gradually displacing the 17 µm sensors. Reducing the distance between pixels on the sensor in combination with the same focal length of the lens increases the base optical magnification and consequently reduces the field of view of the thermal vision device. Thus, thermal vision devices with a lens focal length of 50 mm and a pixel pitch of 12 µm typically have around 15 m of field of view at a distance of 100 m. This is not bad, but monoculars are used to observe the surroundings, and every additional meter of field of view is beneficial. This is especially noticeable when scanning terrain at shorter distances, such as wild boar hunting at a bait site, where typical observation does not exceed a distance of 50 m, effectively halving the device’s already reduced field of view.

A new class of thermal vision monoculars with large sensors, a pixel pitch of 12 µm, and lens focal lengths of 35 mm or even just 25 mm has quickly emerged on the market. These devices combine the advantages of a large field of view provided by a large sensor while maintaining image quality and detail display at a sufficiently high level for modern standards. The amount of detail a thermal vision device will display primarily depends on the pixel pitch of the sensor and the focal length of the lens. When dividing the pixel pitch by the focal length of the lens, we get the angle in milliradians (MRAD) under which the sensor covers the observed object.

  • For a device with 12 µm and a 35 mm focal length lens: 12/35=0.34 mrad.
  • For a device with 17 µm and a 50 mm focal length lens: 17/50=0.34 mrad.

At a distance of 100 m, both devices theoretically cover an area of 34 mm with one sensor pixel, offering an equal level of detail in observing the object. This calculation demonstrates that thermal vision monoculars with 12 µm and a 35 mm focal length lens can provide an equally detailed image as older monoculars with 17 µm and a 50 mm focal length lens. The lenses of thermal vision devices are made of Germanium, which is not cheap as it is used in various cutting-edge electronics applications. Using lenses with a 35 mm focal length instead of 50 mm significantly contributes to lower manufacturing costs of the thermal vision device.

  Steiner Nighthunter H35 GEN II
Sensor640×512 pixel 12 µm NETD <35 mK
LensF35/1.0
MagnificationOptical 2x Digital 8x (2x, 4x, 8x)
Field of view12.50 x 9,40 21.7 m/100 m
Detection range1800m
DisplayOLED 1280×960
Power supply2×18650 Li-ion batteries (not included) Run time up to 8,5h USB – C connector
Dimensions210x80x68 mm 514g with batteries
ProtectionWaterproof
Video/photo recordingResolution: 1024×768 Format:       mp4 / .jpg 32GB internal memory
Table of specifications

Image Quality

The quality of displayed details in the Steiner Nighthunter H35 GEN II should theoretically be similar to older devices with a 50 mm focal length lens. However, other factors, such as NETD, screen quality, and algorithms used by the processor to convert captured data into a visually perceptible image on the screen, also influence the final image quality. During our test, it was evident that the image in the Steiner Nighthunter H35 GEN II monocular was entirely correct and of high quality when the device was used in favourable atmospheric conditions for thermal imaging. The image of living beings was quite detailed and stood out vividly from the cooler surroundings.

Steiner Nighthunter H35 GEN II in action (Source: Steiner)
Steiner Nighthunter H35 GEN II in action (Source: Steiner)

Issues with image quality, especially in displaying details of the surroundings, arose in the following three scenarios. Firstly, when there was more than 90% humidity in the atmosphere, secondly in foggy conditions, and thirdly when we were in the hunting ground during or immediately after rain. In the first two cases, the overall image quality suffered. The detection range was significantly reduced, and warm objects in the image appeared blurred, as if behind a filmy curtain. Consequently, much fewer details of the target were displayed, and the surroundings were shown more or less as a uniformly coloured background as if the animal were standing in a studio between walls without vegetation and other objects. In such cases, it became much more challenging to orient oneself, determine the location of the target in space, assess its distance, and safely shoot in the direction of the target. In the third scenario, during or immediately after rain, the Steiner Nighthunter H35 GEN II displayed living beings sharply and in detail, but the surroundings were equally indistinct and homogeneous as in the first two cases.

The poorer quality of image display in challenging atmospheric conditions for thermal imaging is attributed to the NETD value of <35 mK, which limits the device’s ability to distinguish extremely small temperature differences in the environment that occur in the specific situations mentioned earlier. To be fair, all thermal vision devices face challenges in such weather conditions, but those with truly top-notch NETD values (<25 mK, <20 mK, or even <18 mK) tend to handle them more successfully.

In good atmospheric conditions, with the Steiner Nighthunter H35 GEN II, we could identify the type of game at distances of around 200 m when it was stationary and at distances of 400-500 m when the game was in motion. It is important to emphasize that recognizing the type of game and other living beings through thermal vision devices based on movement characteristics requires a certain level of experience, which can only be gained in the field with a thermal vision monocular in hand.

The test was conducted at the end of November and the first days of December. During this time, deer bucks had already shed their antlers, so evaluating the sensitivity of the device in this regard was not possible. Based on the display of environmental details, we estimate that at distances of around 50 m and closer, the Steiner Nighthunter H35 GEN II would display the antlers of roe deer and red deer, but only in good conditions. Gender recognition of deer was possible based on other body characteristics, and we can assure that at distances where wild boars are typically hunted at feeding sites, it would be possible to identify adult wild boars by gender. In good conditions, the Steiner Nighthunter H35 GEN II accurately depicted various objects in the hunting ground, allowing us to orient ourselves in space and satisfactorily estimate distances to the target based on prior knowledge of the hunting ground.

Steiner Nighthunter H35 GEN II in action (Source: Steiner)
Steiner Nighthunter H35 GEN II in action (Source: Steiner)

The Steiner Nighthunter H35 GEN II allows the user to choose from 6 different colour palettes for displaying the thermal object: White Hot, Black Hot, Red Hot, Iron-Red, Fire in Amber. As usual, we will avoid advising on which colour an individual should choose, as one can determine it through experience with the device. In our case, we mostly used the White Hot colour palette, which covered most of the screen with a darker background of the cold environment, aiming to reduce the loss of night vision. When needed, we quickly switched to Black Hot, but we did not use the other color combinations. However, they are available for users, and with some practice using the thermal vision device, each individual will quickly find the colour palette that suits them best.

The quality of image display is heavily influenced by the thermal vision device’s screen. The Steiner Nighthunter H35 GEN II is equipped with a large OLED screen with a resolution of 1280×960 pixels. This large screen complements the wide field of view covered by the device’s thermal sensor. The image on the screen is clear, and the good resolution does not strain the eyes during prolonged use of the device.

The Steiner Nighthunter H35 GEN II allows up to 8x digital image zoom, which, combined with the basic 2X optical magnification, provides a total magnification of 16x. Of course, when using digital zoom, a pixelated image occurs, but with the Nighthunter H35 GEN II, this is not too distracting up to around 6x total magnification. The digital zoom feature includes not only the usual digital zoom increments of 2x, 4x, and 8x but also finer adjustments in 0.5x steps. The digital zoom is controlled with two buttons, enabling both zooming in and out, not just upwards from 2x to 8x and then back to the basic optical magnification. A short press on one of the zoom buttons changes the magnification by 2x, while a longer press on the same button changes it by 0.5x. This allows for precise adjustment of the magnification to the desired size of the image, considering the trade-off between image quality degradation and the onset of pixilation, which can be quickly reduced with the opposite button.

The Steiner Nighthunter H35 GEN II allows for a three-step change in image mode. Initially set in Standard mode, it also offers Improved and Discovered modes. This function is similar to the enhancement of the thermal vision signal offered by other manufacturers for use in poorer thermal vision conditions. Most of the time, we kept the image mode set to Standard. In foggy conditions, we tested the Improved mode, which slightly sharpened warm objects. However, the usefulness of the Discovered mode remained a puzzle, as we couldn’t find a practical use for it. When activated, the screen completely darkens, with only the warmest objects remaining visible. Perhaps the purpose of this mode is to create an even greater contrast between cold and warm objects in the device’s field of view. However, considering the overall excellent contrast of warm objects in the images of all thermal vision devices, such a mode is entirely unnecessary. In this mode, we lose the overview of the surroundings and the position of the observed living being in space, which is unacceptable for safe hunting.

Ergonomics and Operation of the Device

The design of the Steiner Nighthunter H35 GEN II is one of the strong points of this device, although there is still room for improvement. The device is relatively compact and doesn’t hinder the user too much when used alongside other hunting equipment. To fit into the pockets of a hunting jacket, the pockets need to be fairly large and empty. Pulsar’s Axion series monoculars, at least in terms of compactness, currently have no competition compared to the Steiner Nighthunter H35 GEN II. Due to the use of two 18650-type batteries placed side by side in the lower part of the device, it is slightly wider at the bottom. This, however, allows for stable support on the edge of a hunting blind or another object from which the surroundings are observed.

The housing is made of polycarbonate and additionally, rubber-coated, which Steiner calls Makrolon technology. It feels precisely and well-made to the touch, although it may appear somewhat fragile and not robust at first glance. However, Steiner assures on its website that the Makrolon technology provides their devices with the robustness required for military as well as civilian applications.

The wrist strap holding the monocular can be adjusted to the left or right side, but we found that it kept coming loose after installation, so we eventually removed it after a few outings. Due to the shape of the device, it fits nicely in the hand, and we didn’t miss the strap. When we needed to move the device away from our eye, we simply let it hang on our chest using a neck strap.

The arrangement of buttons on the device is somewhat different from the most well-known manufacturers, but users quickly adapt to the commands, which are well thought out. The power on/off button is located on the lower part of the housing in front of the battery compartment door. The placement prevents accidentally pressing the on/off button while pressing the function keys, which, in the best case, would put the device into “sleep” mode, and in some devices, turn it off. With the Steiner Nighthunter H35 GEN II, there is no such risk, as you will press the on/off button only when you consciously want to.

Steiner Nighthunter H35 GEN II buttons (Source: Steiner)
Steiner Nighthunter H35 GEN II buttons (Source: Steiner)

The button for video recording and capturing clips is unique. A long press triggers video recording, while a short press captures a photo. During testing, we noticed that video recording does not allow simultaneous sound recording, which is somewhat unusual in today’s times. The up/down and left/right buttons allow changing the digital zoom, switching colour palettes, and changing the image mode during standard device operation. In conjunction with the MENU button, all four buttons serve for navigation within menus and submenus.

Calibrating the thermal sensor occurs in three standard modes (automatic, semi-automatic, or manual), similar to most established manufacturers. However, during use, we noticed that sensor calibration in automatic mode is somewhat unevenly distributed in terms of time. This applies both to the time between two calibrations and the time the sensor takes to perform each calibration. The latter was quite unusual, as the calibration time, when the image in the device freezes, ranged from an extremely short 0.5 s to an almost unbelievable 4 s, with all possible intermediate variations.

Steiner declares the device as completely waterproof, but it does not specify the IPX standard to which it belongs. The operating temperature range is between -10 to +50 degrees Celsius. In conditions that occasionally occur in winter in Slovenia, we would appreciate the possibility of using the device in even colder air. However, given the autumn testing period, we could not evaluate the performance of the device in such cold weather.

Power Supply

The Nighthunter H35 GEN II is powered by two standard 18650 batteries, which can be purchased at well-stocked electronics stores. The advantage of using 18650 batteries is that they are inexpensive and readily available. Buyers of the device are not dependent on purchasing a special battery pack, which some manufacturers often offer at a high price. If you have multiple devices in your hunting kit that use batteries of this type, it also reduces the need for carrying numerous spare batteries.

However, there is a wide variety of 18650 batteries on the market, differing in both capacity and manufacturing quality. The capacity of these batteries ranges from 1800mAh to 4000mAh. Due to this variation, Steiner’s claim about the operating time of the Nighthunter H35 GEN II becomes challenging to verify. Especially considering that the package does not include at least two battery inserts that could serve as a standard for measuring the device’s operating time. The manufacturer states that the device will operate for at least 8.5 hours with two fully charged batteries. During testing, we repeatedly verified this claim and measured the number of hours the device could be expected to operate. The average operating time of the device with one fully charged pair of batteries was around 9 hours. It is essential to note that, for testing purposes, we used a pair of entirely new 3000mAh capacity 18650 batteries. Battery endurance testing in the device was conducted by turning it on with fully charged batteries. Our usual 4-5 hour hunting session in temperatures around 0 degrees Celsius was followed by leaving the device on at room temperature until the batteries were depleted.

Steiner Nighthunter H35 GEN II
Steiner Nighthunter H35 GEN II

Steiner recommends using 18650 batteries with a length between 67-71 mm. Batteries of this length have a button on the + pole or have their own protection against overcharging. Since we were not aware of this information before purchasing batteries, we used buttonless 18650 batteries with a length of 65 mm, similar to those used by PARD devices. The device also operated with such batteries, but only when it was not subjected to sudden shocks or vibrations. While wearing it on a neck strap, we experienced instances where the device turned off while walking on uneven terrain causing vibrations. After noticing this behaviour multiple times, we measured the length of the batteries in use. When we replaced them with longer ones, there were no more instances of shutdown even with intentional abrupt shaking, something that cannot occur under normal use.

When using 18650 batteries, special care must be taken for safe handling and storage. Lithium-ion batteries are sensitive to potential damage, which can lead to battery ignition. Caution is also necessary when transporting spare batteries, as storage in the pockets of hunting clothing, mixed with other items such as car keys, can result in a short circuit. We recommend storing batteries in special plastic cases and purchasing well-known brands from trustworthy providers.

The device also operates when directly connected to a power bank. In this case, it is advisable to leave two batteries in the monocular during potential use via the power bank since the USB-C power cable can lose contact while moving, causing the device to immediately turn off. However, if there are at least two minimally charged batteries in the device, there should be enough time to properly secure the cable. Certainly, the device will function when connected to a power bank even without inserted batteries, a scenario we had to test immediately upon receiving the device, as we were surprised to find that Steiner did not include at least two power supply batteries in the package, even though a charger for two batteries is included in the kit.

Package Contents

When purchasing the Steiner Nighthunter H35 GEN II thermal monocular, the buyer receives a soft carrying case, a neck strap, a hand strap, a charger for two batteries with adapters for various types of outlets, a USB/USB-C cable, and a video/USB-C cable.

Notably, the package does not include any paper user manuals; instead, there is a sheet of paper with a QR code that directs users to the electronic version of the user manual online. However, the operation of the device is relatively straightforward, and those familiar with similar devices may not require printed instructions. Apart from the absence of any batteries included with the device, the content of the additional equipment is considered adequate for normal usage.

Connectivity

The Nighthunter H35 GEN II connects with the Steiner Connect application. The interface of the application is somewhat different from similar apps but is logical and entirely functional. The connection to the device worked stably in all conditions. Even in environments with multiple available WIFI networks simultaneously, the connection between the smart device (phone, tablet) remained stable. The application allows for transferring photos and videos, remote control of almost all device functions (except focusing the image), and receiving software updates.

Conclusion

The Steiner Nighthunter H35 GEN II is a very good thermal monocular, particularly when considering the balance between image quality and device compactness. The combination of a large sensor, a pixel size of 12 µm, and a 35 mm focal length lens, provides a very good image within a compact form factor. The use of 18650-type batteries simplifies and makes battery replacement cost-effective. The device’s dimensions allow for easy integration with most other hunting equipment without compromising on what to leave at home due to the thermal monocular. In environments with frequent high humidity and fog, a slightly better NETD would be desirable. The option of a version with a built-in laser rangefinder, a feature offered by almost all competitors in this class, could attract more buyers.

However, it’s crucial to remember that, in addition to all these features, the device carries the prestigious Steiner name on its body and carrying strap, evoking a considerable amount of respect and even a bit of envy among many hunting companions.

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Steiner Nighthunter H35 GEN II Field Test
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Steiner Nighthunter H35 GEN II Field Test
Description
On our recent test in the hunting ground, we evaluated a thermal vision monocular bearing a resonant name in the field of hunting and shooting optics. However, the fact remains that thermal vision technology and traditional optical devices based on glass lenses share little in common.
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Optics Trade
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