Thermal and night vision devices: how to choose between thermal, digital and multispectral

Thermal and night vision devices: how to choose

A thermal imager and a night vision device both help you see when the naked eye is not enough, but they work in completely different ways. A thermal device “sees” the heat emitted by animals and objects, even in total darkness; a digital night vision device captures visible and infrared light with a sensor similar to a camera’s, assisted by an IR illuminator. Then there are multispectral devices, which combine both channels in a single instrument.

In this guide we look at how the different technologies work, which technical specifications really matter (sensor resolution, NETD, objective lens, detection range, display, battery), the differences between monocular, binocular, riflescope and clip-on, how to read Nocpix and HIKMICRO model codes and the main fields of use, with a brief note on Italian legislation. Technical data are those declared by the manufacturers.

Thermal, digital night vision or multispectral: the differences

How a thermal imager works

Every body emits infrared radiation according to its temperature. The heart of a thermal imager is an uncooled microbolometer, almost always made of vanadium oxide (VOx): a pixel array that measures the smallest temperature differences in the scene and turns them into an image. A thermal device needs no light at all, works the same way by day and by night and makes a warm animal stand out even when it is camouflaged in vegetation.

It does have limits, however: it cannot see through glass (a car window or the glass of a hide blocks the image), it does not show colours and details like a conventional optic, and the image loses contrast when everything has the same temperature, for example after prolonged rain.

How a digital night vision device works

A digital night vision device uses a highly sensitive CMOS sensor, like that of a video camera. By day it delivers a colour image; at dusk and at night it uses residual light and, above all, a built-in or add-on infrared illuminator that lights the scene with light that is invisible (or nearly invisible) to the human eye. The image is more “natural” and detailed than a thermal one, which helps in identifying the animal, but night-time range depends on the power of the illuminator and is much shorter than the detection range of a thermal device.

There are also analogue image intensifier tube night vision devices (the so-called generations), which amplify residual light. They are a different technology and are not covered in this guide.

Multispectral: thermal and digital in a single instrument

Multispectral devices integrate a thermal channel and a digital channel, often with a laser rangefinder. The thermal channel lets you detect the animal even at long distances; you then switch to the digital channel to observe it in detail. This is the approach of the HIKMICRO HABROK and Nocpix OMNI series.

The technical specifications that matter

Sensor resolution

This is the number of pixels of the microbolometer and the most important specification of a thermal imager: more pixels mean sharper outlines, more detail and an image that holds up better when zoomed. It should not be confused with the display resolution, which is almost always higher.

• 256×192: entry level, suitable for short- and medium-range observation and for locating game.
• 384×288: a good balance between price and performance for hunting at medium distances.
• 640×512: according to Nocpix, the most balanced choice for most hunters, with markedly superior detail even when zooming in.
• 1280×1024: currently the highest available for civilian use, for those who observe at long range and want the best definition.

Pixel pitch

This is the distance between the centres of two adjacent pixels, in micrometres (µm). Today the standard is 12 µm, while older models used 17 µm. A smaller pitch allows more compact sensors and, with the same objective lens, a higher base magnification.

Thermal sensitivity (NETD)

NETD (Noise Equivalent Temperature Difference) is the smallest temperature difference the sensor can distinguish, expressed in millikelvin (mK). The lower, the better: the image stays contrasted and detailed even in rain, fog, high humidity or when the animal has a temperature similar to the background. Nocpix recommends values of around 20 mK or lower; the latest Nocpix and HIKMICRO models declare ≤15 mK and the Nocpix ACE 2 series reaches ≤12 mK.

Objective lens: focal length and aperture

The focal length of the objective lens (in mm) determines the base magnification and the field of view: a short focal length covers a wide area, ideal for scanning the terrain and moving through woodland; a long focal length magnifies more but narrows the field, and is suited to observing at long range. The aperture (F0.9 – F1.2) indicates how much thermal energy the lens gathers: lower values give a brighter, more contrasted image.

This is clear when comparing the HIKMICRO LYNX 3.0 monoculars:

Resolution also affects the field of view: the Nocpix QUEST H50R binocular (640×512, 50 mm) covers 15.4 × 12.3 m at 100 m, while the QUEST S50R, with the same lens but a 1280×1024 sensor, reaches 30 × 24 m while keeping a sharp image.

Magnification and digital zoom

The magnification of a thermal imager starts from a base (optical) value and continues with digital zoom, which enlarges the image without adding information: beyond a certain point the image becomes grainy. This is why a high-resolution sensor is appreciated above all when zooming in. Some models, such as the Nocpix ACE riflescopes, add an optical eyepiece zoom that magnifies without loss of definition.

Detection, recognition and identification range

The range given in product specifications is almost always the detection range: the distance at which a target of about 1.7–1.8 m (Nocpix uses a 1.7 × 0.5 m target) covers a couple of pixels. It means seeing that “there is something warm”, not understanding what it is. The calculation is based on the Johnson criteria, under ideal conditions:

• Detection: the target covers about 2 pixels; a heat source is perceived.
• Recognition: about 6 pixels, so around one third of the detection range; you can tell the type of animal.
• Identification: about 12 pixels, around one sixth of the detection range; details can be assessed.

In practice, with fog, rain or vegetation, real distances are shorter. To compare two models it is more useful to look at resolution, objective lens and NETD than at the detection figure alone.

Frame rate

This indicates how many times per second the image is refreshed. Hunting devices run at 50 or 60 Hz: a smooth image when following a moving animal or panning. Low values (5–10 Hz, typical of some smartphone thermal cameras) give a jerky image.

Display

The display is what the eye actually looks at. Recent models use OLED or AMOLED microdisplays, with deep blacks and high contrast. They range from 1024×768 on entry-level models to Full HD 1920×1080, up to the 2560×2560 circular displays of the Nocpix ACE riflescopes. A good display makes the image easier to read, but does not add detail if the sensor is low resolution.

Colour palettes

The thermal image can be displayed with different palettes: White Hot (heat shown in white, the most widely used), Black Hot (heat shown in black, more natural for some users), Red Hot (highlights the hottest sources in red) and colour or fusion palettes. Dark or red/green palettes cause less eye strain and interfere less with the eye’s adaptation to darkness.

Calibration and shutterless technology

To keep the image uniform, the thermal sensor must calibrate periodically. In traditional models an internal shutter closes for an instant, with a small “click” and a momentary freeze of the image. Shutterless technologies, such as HIKMICRO’s HSIS system, perform calibration in the background without interrupting the view.

Built-in laser rangefinder

Many models have a laser rangefinder (L in HIKMICRO codes and R in Nocpix codes) that measures the distance to the target, typically up to 1,000–1,200 m. In a riflescope the rangefinder works with the ballistic calculator to correct the point of impact according to distance.

Battery, runtime and ruggedness

• Battery: replaceable 18650 batteries let you swap the battery in the dark in a few seconds; some models combine a built-in battery and an 18650 for longer sessions.
• Runtime: declared runtimes generally range from 4 to 8 hours and decrease in cold weather, with Wi-Fi on and while recording.
• Sealing: IP67 protection ensures resistance to rain and temporary immersion.
• Recording and apps: internal memory (16–64 GB), photos and video, Wi-Fi and dedicated apps for streaming to a smartphone. On riflescopes, recoil-activated recording is a useful feature.

Digital night vision: 850 or 940 nm IR illuminator

In digital devices, night-time range depends on the infrared illuminator, and the wavelength makes the difference:

• 850 nm: reaches further and gives a brighter image, but the emitter produces a faint reddish glow that is visible at close range.
• 940 nm: practically invisible, so more discreet with game, but with the same power it has a shorter range.

HIKMICRO indicates the wavelength in the model name: versions with the letter N (for example the CHEETAH C32F-SN or HABROK 4K HE25LN) use the 940 nm illuminator. On ALPEX riflescopes the illuminator is added with the HM-L128IR 850 nm or HM-L129IR 940 nm IR torches, while the Nocpix NITE D70R has dual-band 850/940 nm illuminators.

Monocular, binocular, riflescope or clip-on

Thermal monocular: the tool for searching

The monocular is the most popular type of thermal imager: lightweight, it is held in one hand and used to scan the terrain, locate game and check the area before and after the hunt. For moving through woodland a short focal length and a wide field are best; for observing meadows and clearings at a distance, a focal length of 35 mm or more. In our catalogue you will find the Nocpix LUMI and VISTA series and the HIKMICRO LYNX, FALCON and CONDOR series.

Thermal and multispectral binoculars: observing for long periods

A binocular is used with both eyes: it is less tiring during long observation sessions, for example from a high seat, and is held like a traditional binocular. It weighs and costs more than a monocular. The series in our catalogue are Nocpix QUEST (thermal only, with rangefinder) and OMNI (multispectral) and HIKMICRO HABROK and RAPTOR (multispectral).

Thermal or digital riflescope

A thermal or digital riflescope has an electronic reticle and is mounted on the firearm like a conventional scope, with compatible rings or mounts. In addition to the parameters already covered, what matters is the declared recoil resistance, the eye relief (the longer it is, the safer the scope with powerful calibres), the storable zeroing profiles for different firearms or ammunition and the precision of the adjustment clicks.

In our catalogue you will find the Nocpix ACE, ACE 2 and BOLT and HIKMICRO STELLAR, PANTHER, NEOS and THUNDER thermal riflescopes, as well as the HIKMICRO ALPEX and CHEETAH and Nocpix NITE day/night digital riflescopes. Digital riflescopes are the most affordable solution for those looking for a scope that can be used both by day and by night.

Thermal or digital clip-on: no need to change your scope

A clip-on is mounted in front of the objective lens of a daytime riflescope, using an adapter, and adds thermal or digital vision while keeping the scope’s reticle and zero. It is the choice for those who want to use the same firearm and the same scope by day and by night. You need the right adapter for the diameter of the scope’s objective lens (HIKMICRO offers THUNDER adapters in 50 mm and 56 mm, as well as other sizes) and it is best used at low or medium magnifications: manufacturers state the maximum recommended scope magnification. With the dedicated eyepiece, many clip-ons can be turned into a monocular.

In our catalogue: Nocpix MATE LITE, MATE H38R and MATE H50R, HIKMICRO THUNDER TH35C 3.0, THUNDER TE19CR 2.0 and the CHEETAH digital clip-ons.

2-in-1 devices

Some models are designed for dual use. The Nocpix SLIM L35 and SLIM H35 can be used as a handheld monocular or as a riflescope and, with the quick-release mount, switch from one mode to the other without re-zeroing.

How to read Nocpix and HIKMICRO model codes

The model codes of both brands follow a precise logic: a letter indicates the thermal sensor resolution, the number the focal length of the objective lens in millimetres and a suffix the additional features.

• Watch out for the letter H: for Nocpix it means 640×512, for HIKMICRO 384×288. The exception is the LYNX LH15 3.0, which according to HIKMICRO has a 320×240 sensor.
• Number: the focal length of the thermal objective lens, for example 35 = 35 mm.
• Laser rangefinder: suffix R for Nocpix (VISTA H50R), L for HIKMICRO (LYNX LQ35L, FALCON FQ50L).
• HIKMICRO N: 940 nm IR illuminator (HABROK HQ50LN, CHEETAH C32F-SN).
• Nocpix D: day/night digital channel (NITE D70R, NITE PRO D50R).
• Version: “2.0” or “3.0” indicate the generation of the HIKMICRO series, “ACE 2” the second Nocpix generation.

Nocpix and HIKMICRO: the ranges in our catalogue

Nocpix

Nocpix is a brand specialising in thermal imaging for hunting, with 12 µm VOx sensors and NETD down to ≤12 mK, AMOLED displays (Vision+) and Reality+ (R+) image processing.

• LUMI: compact monoculars with F0.9 lenses, from the LUMI P13 (256×192) to the LUMI H35 (640×512), also available with rangefinder (L35R, H35R).
• VISTA: high-end monoculars with rangefinder and stabilisation, such as the VISTA H50R.
• QUEST: thermal binoculars with 1,000 m rangefinder and dual battery (H35R, H50R, S50R).
• OMNI: multispectral binoculars with 8K digital channel, thermal channel and rangefinder (L19R, H35R).
• ACE and ACE 2: thermal riflescopes with 2560×2560 display, eyepiece zoom, rangefinder and ballistic calculator, such as the ACE 2 H35R.
• BOLT: thermal riflescopes with rangefinder, from the BOLT P25R to the BOLT H50R.
• MATE, SLIM and NITE: thermal clip-ons, 2-in-1 devices and day/night digital riflescopes.

HIKMICRO

HIKMICRO is one of the leading manufacturers of thermal cameras and covers every type of device, from entry-level monoculars to professional multispectral binoculars.

• LYNX 3.0: compact monoculars with shutterless technology, from the LYNX LE10 to the LYNX LQ35L with rangefinder.
• FALCON and CONDOR: monoculars with 640×512 sensor, also available with rangefinder (FALCON FQ50L, CONDOR CQ35L).
• GRYPHON: multispectral monocular with image fusion (GH25).
• HABROK and RAPTOR: multispectral binoculars with 4K digital channel and rangefinder, from the HABROK 4K HE25L 2.0 to the HABROK Pro HX60LS with 1280×1024 sensor.
• STELLAR, PANTHER, NEOS and THUNDER: thermal riflescopes and clip-ons.
• ALPEX and CHEETAH: day/night digital riflescopes and clip-ons, such as the ALPEX 4K LRF A50EL with rangefinder.

Our catalogue also includes thermal and night vision devices from other brands, such as the Vortex Veil 400 monocular, the Konus Fiery thermal devices and the Sightmark Wraith digital riflescopes.

Fields of use

• Selective hunting and ungulate control: locating and assessing animals at dawn, at dusk and, where permitted, at night; the binocular or monocular remains the search tool even when a riflescope is used.
• Recovering wounded game: a wounded animal stays warm and visible to a thermal device even in dense vegetation.
• Safety: before taking a shot, a thermal device helps check that there are no people, dogs or other animals in the area or behind the target.
• Wildlife observation: following nocturnal wildlife without disturbing it, population counts and documentation with photos and video.
• Agriculture and property: checking fields and fences against wild boar damage, monitoring pets and livestock.
• Outdoor and search: night hiking, finding a hunting dog or a lost animal, and search and rescue activities.

What Italian law says

In Italy, the use of these devices while hunting is governed by Italian national law 157/1992 (legge 157/1992) and by regional rules and hunting calendars. In summary:

• Italian Decree-Law 63/2024 (decreto legge 63/2024, converted into law by legge 101/2024) added paragraph 2-ter to article 13 of law 157/1992, which allows the use of aiming devices, including digital ones, for night vision in selective wild boar hunting. Devices classified as military equipment (Italian law 185/1990, legge 185/1990) are excluded. The Italian Regions have transposed the provision into their hunting calendars.
• For other types of hunting, Italian case law (for example the Court of Cassation, Cassazione, judgment 48459/2015) has considered a night vision device mounted on a firearm to be a prohibited means.
• Wildlife control activities (article 19 of law 157/1992) are carried out according to regional plans, which establish who may take part, at what times and with what means.

The rules vary from Region to Region and are updated frequently: before using a night vision or thermal device while hunting or during wildlife control, always check the hunting calendar and the plans of your Region. The information in this section is for general information only and does not replace the legislation in force.

Which one to choose based on use

Pre-purchase checklist

• Technology: thermal for detection, digital for seeing details at a lower cost, multispectral to have both.
• Type: monocular, binocular, riflescope, clip-on or 2-in-1.
• Sensor resolution: at least 384×288 for medium-range hunting, 640×512 as the most versatile choice.
• NETD: 20 mK or less.
• Objective lens: short focal length for woodland, long for open spaces.
• Rangefinder: useful for estimating distance and essential for ballistic calculation.
• Battery: declared runtime and whether it can be replaced in the field.
• Accessories: mounts, clip-on adapters, IR illuminators, cases.
• Legislation: check what is permitted in your Region.

You will find all models in the Thermal imaging devices and Night vision devices collections and on the Nocpix and HIKMICRO brand pages. Mounts, adapters and batteries are in the Optics accessories section. For advice on the most suitable model, feel free to contact us.