What is the Difference Between Thermal and Night Vision?

Resource Description

Thermal and Night Vision

Sight is considered to be the most important human sense. Scientific studies show that visual perception provides up to 80 percent of all information we get about the surrounding. But like everything else, human sight is not perfect. Our eyes interpret objects using light in the visible spectrum reflected by them. Thus, the less light, the worse we see. Imperceptible during the daytime, it represents quite a big problem at night. Here is where night and thermal vision come in handy. Designed to increase the possibilities, they are irreplaceable for a number of professionals and amateurs whatever the sphere is.


How do they work?

Although many people confuse thermal and night vision, these technologies are completely different. To better understand the difference between them, let’s find out the basic operating principles.

Night Vision

As well as the human eye, night vision devices (NVDs) sense optical radiation. Any NVD consists of an objective lens, an eyepiece, and an image intensifier tube. Its operating principle is simple: an image intensifier tube increases the intensity of light gathered by a lens.

Basically, an NVD works in the visible light spectrum and in part of the near-infrared one. The device captures the light coming from the moon and stars or an artificial source. The light photons are transformed into electrons, which are then amplified to a much greater number through an electrical and chemical process. Finally, the device changes the amplified electrons back into visible light that you see through the eyepiece. The image may be clear green or black-and-white, depending on the image intensifier tube inside (Picture 1).


This design is used in any generation of NVD. The only difference between Gen 1, Gen 2, and Gen 3 is in the capabilities of an intensifier tube.

An NVD can also have an in-build IR illuminator that provides the device with an additional IR source, making it possible to use an NVD in the dark. Although IR radiation is invisible to the human eye, it can be detected with either a night or thermal vision device that is critical for some specific applications.

Thermal Vision

In contrast to NVDs, thermal imagers work in the infrared spectrum of light. Each object, either animate or inanimate, emits infrared waves in the form of heat. These waves are captured and transmitted by the IR objective lens made of germanium. The infrared detector, composed of tiny sensitive elements commonly known as pixels, read the waves, generating electronic impulses with different values. These impulses are then processed by the electronics into a digital image (Picture 2). Thermal imagers show not only heat but the minute difference in it, enabling the user to see the objects well.

Night Vision

Remember, thermal imagers cannot identify objects behind the glass or other solid items. They can only detect the heat emitted by the surface.

What's the difference?

As noted earlier, thermal and night vision operating principles are completely different. Unless it has an IR illuminator, an NVD is useless when there is no light at all, whereas a thermal imager will perfectly do its job even in total darkness as well as in the rain or thick fog. Night vision provides a more natural image that gives an opportunity not only to see the presence but also to identify the object. However, with an NVD, it’s difficult to see a person in disguise, while the thermal technology can detect even residual heat, such as hand- and footprints.

Night Thermal
Needs a source of light Works in the dark, fog, and rain
Provides a natural image Shows the picture in the IR color spectrum (from purple to red)
Enables identifying the objects Shows the presence of the objects
Cannot identify a disguised person Detect hand - and footprints
Able to "see" through solid objects Cannot detect objects through glass
More lightweight Larger and heavier
Less expensive More expensive

Which is better?

It’s hard to say which technology is better. Both night and thermal vision devices have their own features, capabilities, price levels, and applications. Identifying people, NVDs are widely used in military and police as well as surveillance. Detecting objects through solid objects, they provide a wider view.

How to choose?

Choosing between night and thermal vision devices, answer the following questions:

  • What application will it be used for?
  • Do you need to identify objects or detect the presence only?
  • Is the temperature of the detected objects important?
  • Do you need to be invisible to those who can detect IR radiation?
  • Do you need to detect items behind solid objects?
  • Does the weight matter?
  • What sum of money are you ready to spend?

If your answers are contradictory, consider buying a 2-in-1 device, capable of switching between night and thermal vision.

At Prime Buy, you can find an extensive variety of night vision devices and thermal imagers in different designs and form factors from the most trusted brands, including ATN, which is known as a trusted market-leading supplier of best-in-class optics solutions.

Search for the cutting-edge night and thermal cameras, goggles, monoculars, scopes, cameras, and more at Prime Buy right now!

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