ThermTec iBEX 635L Thermal Riflescope

Thermal imaging and laser ranging in one riflescope

The ThermTec iBEX 635L combines a high-resolution 640×512 thermal imaging sensor, a 35mm objective lens and an integrated laser rangefinder in one riflescope body. You can locate a warm subject, take a distance reading and keep the subject in view through the same eyepiece, without switching to a separate handheld rangefinder.

Because the 635L images heat rather than reflected light, it does not rely on an infrared illuminator to form its picture after dark. That is the key practical difference from many digital night vision scopes. If you are still weighing up the two technologies, our thermal rifle scopes category brings the thermal options together for comparison.

iBEX 635L specifications

These figures are ThermTec’s published specifications for the iBEX 635L, available in the Manufacturer iBEX 635L datasheet.

To see where this model sits among ThermTec’s other thermal optics, browse the full ThermTec range.

Base magnification, digital zoom and field of view

With its 35mm objective and 640×512, 12µm sensor, the ThermTec iBEX 635L has a 2.2x base magnification and a field of view of 12.5° wide by 10° high. The base view is the one to scan with, since it shows the widest area.

The 1–4x digital zoom enlarges the base image electronically, providing a maximum combined magnification of 8.8x. A subject appears larger on screen, but digital enlargement does not add detail the sensor has not captured. Therefore, it is best used for a closer look at something you have already located at base magnification.

The 50Hz refresh rate helps keep the image smooth as you pan, while the 1600×1200 AMOLED display presents it to the eye. The NETD of under 18mK describes how finely the sensor separates small temperature differences. This matters when a subject is only slightly warmer than the ground or cover around it.

Detection range and laser ranging answer different questions

ThermTec quotes two distance figures for the iBEX 635L, and each measures something different:

• Detection range, up to 1800m (manufacturer advertised): How far away a heat source can appear as a visible signature. Detection means a warm shape shows in the image, not that you can tell what it is.
• Laser rangefinder, up to 1000m (manufacturer specification): The furthest distance the integrated LRF is specified to measure.

Neither figure is an identification distance. Recognising or identifying a subject generally takes a shorter distance than detecting it. This depends on the subject’s size, its temperature contrast with the background and the conditions at the time.

Power and mounting

Replaceable 18650 battery

The ThermTec iBEX 635L runs on a replaceable 18650 rechargeable cell, a widely used battery format. ThermTec quotes up to 6 hours of runtime per battery. However, actual use varies with temperature, cell condition and the functions in use, such as the rangefinder.

Because the cell can be removed, a charged spare lets you carry on during a long session rather than waiting for a recharge. The iBEX 635L also comes with two 18650 batteries, making it practical for extended use in the field.

30mm ring interface and weight

The scope body takes standard 30mm rings. Choose a set that also suits your rifle’s rail and gives the mounting height your setup needs.

The manufacturer quotes a weight of 770 ±5g for the ThermTec iBEX 635L. When comparing it with other thermal riflescopes, check whether the stated weight includes the battery, as this can affect the overall mounted weight.

Frequently asked questions

Is the ThermTec iBEX 635L a thermal scope, or does it need an IR illuminator?

It is a thermal riflescope. It forms its image from the heat subjects give off, so it needs neither visible light nor an infrared illuminator to produce a picture in the dark. Digital night vision scopes, by contrast, generally rely on IR illumination after dark.

How far can the ThermTec iBEX 635L detect, and how far can its rangefinder measure?

ThermTec advertises a detection range of up to 1800m and specifies the integrated laser rangefinder to measure up to 1000m.

The first figure is how far away a heat signature can appear in the image. The second is the longest distance the rangefinder is specified to measure. Neither tells you how far away you can identify a subject.

What is the base magnification and field of view of the iBEX 635L?

The manufacturer’s specifications give the ThermTec iBEX 635L a 2.2x base magnification and a 12.5° × 10° field of view.

The 1–4x digital zoom then enlarges the base image up to four times, providing a maximum combined magnification of 8.8x. This makes subjects larger on screen without adding sensor detail.

Which battery does the ThermTec iBEX 635L use, and how long does it run?

It uses a replaceable 18650 rechargeable battery, with a manufacturer-quoted runtime of up to 6 hours per cell.

Runtime varies with temperature, battery condition and the functions in use. As the cell is removable, carrying a charged spare is a straightforward way to extend a session. Two rechargeable 18650 batteries are included with the iBEX 635L.

Will the ThermTec iBEX 635L fit my existing scope rings?

The scope has a 30mm ring interface, so it needs 30mm rings.

If your current rings are 30mm and suit your rifle’s rail and the mounting height you need, they are the right size for the iBEX 635L. Rings made for a different tube diameter are not.