How to choose a thermal imaging device

Thermal imaging devices appeared later than night vision devices, EOP and digital devices. Unlike night vision devices, which amplify a weak light signal tens of thousands of times, thermal imaging devices are more advanced because they are not afraid of light and can work at any time of the day due to their ability to react to heat, recognizing objects by their thermal background.

Purpose and operating conditions

First of all, decide why you need a thermal imaging device:

• Hunting - image quality, detection range, lightness of the device and autonomy are important.
• Tactical tasks/service applications - critical reliability, ability to mount on various platforms, protection against moisture and shock.
• A device with a fixed focus but a wide viewing area may be suitable for surveillance/security purposes.

Thermal imaging devices are especially needed when hunting ungulates and predators, regardless of the method - whether it is an approach or observation from a tower. The main task is to detect the beast. For these purposes, thermal imaging devices with a maximum detection distance of a human-sized target of 500 meters and a frame refresh rate of 30 Hz are suitable, which will provide a smooth and natural image, which is important when hunting fast-moving targets. To obtain a clear thermal picture and good detail of the target, it is recommended to use a thermal imager with NETD ≤ 50 mK. It is recommended to take into account the battery life and the degree of moisture protection not lower than IP67. In addition, the devices are classified by type of mounting: 30-mm rings and brackets.

Budget thermal imaging devices, unlike premium ones, do not have such high technical characteristics and functions, but they cope perfectly with the most necessary hunting tasks, showing themselves effectively at close and medium distances.

How does a thermal imaging device work?

Any object – a person, an animal or an object – emits infrared waves invisible to the eye. The higher the temperature of the body or object, the more intense this radiation. Thermal imaging devices record this radiation. Hunting models display information in the form of a heat map - a high-contrast image on which it is easy to recognize the target, even in the dark.

What is the difference between a thermal imaging device and a night vision device?

The main difference between a thermal imaging device and a night vision device is in the principle of image formation. Thermal imagers record thermal radiation emanating from objects and display temperature differences using different shades and color gradations: the higher the temperature, the brighter the object appears on the screen. They work even in complete darkness and allow you to see heat traces.

Night vision devices, on the other hand, amplify weak light, such as moonlight or starlight, magnifying it tens of thousands of times. However, they do not work without residual light or infrared illumination and are sensitive to bright light, which can cause blindness or malfunction.

Can a thermal imager "see" through fog, leaves, rain or snow?

Thermal imaging devices are able to distinguish between temperature differences between objects and their surroundings even in difficult weather conditions - such as fog, snowfall or rain, as well as in the presence of vegetation. However, it should be noted that heavy precipitation or dense foliage can reduce the range of the device and make it difficult to accurately identify objects.

Basic principles of choice:

Sensor resolution. The detector's resolution is one of the important parameters. The higher the resolution, the clearer the image, especially when magnified.

• Standard models with resolutions of 256×192 and 320×240 are suitable for working at close and medium distances.
• The medium level – 384×288 – is optimal for hunting at medium distances.
• Premium class with a resolution of 640×480 and higher provides the most detailed image at long distances (Defender 660L).

Display type.

LCOS - is a liquid crystal display on a silicon substrate. In this technology, light is reflected from the surface of each pixel, forming an image.

In OLED - displays, each pixel emits its own light, so there is no need for a separate backlight.

AMOLED is an advanced version of OLED with an active matrix to control each pixel.

The choice depends on the tasks and budget:

• For hunting and standard tasks - LCOS is suitable
• For universal use - OLED will be optimal
• For professionals and those who want the maximum – AMOLED will provide the best picture

Detection range. The range depends on the sensitivity of the sensor, the quality of the lens, and the environmental conditions. Devices with a 35–50 mm lens and a resolution of 384×288 can reliably detect a target at a distance of 1–1.5 km. Premium models allow you to find a person or animal at a distance of up to 2–3 km.

Lens diameter.The higher this indicator, the more heat the device captures and the wider the viewing radius.

A great choice is 25-50 mm lenses.

Devices with smaller lens sizes are suitable for use at short distances.(Defender 319)

Update frequency.

• 25 Hz is sufficient for slow observation and ambush hunting.
• 50–60 Hz – better suited for tracking moving objects, active shooting, and tactical tasks.

Continuous operation time. An important parameter that is worth paying special attention to. The optimal duration of operation on a single charge is considered to be 10 hours, regardless of weather conditions.

NETD sensitivity. The lower the NETD value (e.g. <40 mK), the better the thermal imager can distinguish fine temperature details. This is especially important when hunting in conditions of similar temperatures (humidity, morning dew, etc.).

Weapon mounts and compatibility. Make sure the device can be securely mounted on your weapon. Picatinny/Weaver mounts are the most versatile. Recoil resistance is important (especially for large caliber rifles). Check for parallax adjustment if you plan to shoot at different distances.

Choosing a thermal imaging device is a compromise between tasks, budget and technical capabilities. Clearly determine what is more important to you - range, accuracy, ease of use, or a set of functions. And remember: a quality device is an investment that will provide you with results in any situation, whether hunting or official tasks. For experienced hunters who go hunting every season, as well as novice hunters, we recommend choosing thermal imaging devices Defender

If you want to get a personal recommendation, contact our consultants - we will select a thermal imaging device for your goals and budget.