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The human eye cannot see infrared light since this light lies beyond the visible light spectrum. However, thanks to infrared optics, it’s possible to capture infrared light.

But what is infrared optics?

Infrared (IR) optics refers to any device that can register, display and emit infrared radiation. These devices use optical elements such as an infrared filter, mirror, and infrared lenses to capture infrared light.

An IR lens captures infrared light that is virtually impossible to see with the naked eye. While a normal camera lens captures images of objects that radiate light that is visible to the eye, an infrared lens detects electromagnetic radiation, which is the light that lies beyond the visible spectrum.

Moreover, an infrared lens depends on heat rather than light to record images. Since IR light can be felt as heat, an infrared lens can be able to express the heat value of an object that radiates heat.

Infrared lenses have a wide range of industry applications. For instance, they are used in thermal imaging cameras by medical professionals. IR technology is also used by electricians and building inspectors to detect leaks, corrosion, and other building deterioration dangers.

Want to learn more?

This article explores everything you need to know about IR lenses and how they work.

How Does an Infrared Lens Work?

The human eye is an optical device with a sensor called the retina. Regular cameras work very much like the naked eye, as they receive and turn radiation from the visible light spectrum into an image.

Unfortunately, a normal camera, just like the retina, cannot detect infrared rays.

The good news is that we can use IR cameras to detect this light. Infrared cameras require a custom lens, infrared filters, and sensors to capture IR light.

Notably, infrared camera lenses work differently from regular camera lenses.

An infrared lens works by capturing all the IR light bouncing around and redirects this light to the camera sensor, which helps create a clear thermal image. IR lenses used in infrared cameras capture invisible heat or IR radiation in extended wavelength ranges of 700 to 900 nm or more.


An infrared lens helps to focus the infrared radiation of the object to the camera’s sensor, which generates an amplified electrical signal that is converted to a fine image.

An IR camera lens makes images from thermal radiation, aka infrared or heat. This is why IR camera custom lenses are made of materials such as germanium, silicon, chalcogenide glass, and other substances that have low absorption and are transparent in the infrared spectrum.

Main Advantages of IR Lenses

The biggest advantage of infrared lenses is that they help capture images that the human eye cannot see. This means that an image taken with an infrared lens is very unique and greatly different from what is captured by a normal camera lens.

Other advantages of an IR lens include:

  • • Helps capture images in low light conditions, which is useful in security and surveillance applications
  • • The focus of the lens is consistent with visible light, which makes images clearer
  • • IR lenses use the latest optical design and LD optical glass technology, which helps eliminate the focal plane shift of near-infrared and visible light
  • • In surveillance applications, the IR lens helps keep lighting discreet, helping conceal the camera’s viewing direction
  • • IR lenses have higher penetration rates which is important for use in machine vision and applications with smoke, dust, and fumes
  • • IR lenses are insensitive to moderate vibration
  • • Suitable for scenes with high temperatures as they provide high-precision temperature measurement
  • • IR lens detection distance is very long as it can see a distance of 10 to 30 km or more making it suitable for long-distance illumination
  • • IR lenses are immune to visual limitations


What Are Infrared Lenses Used For?

IR lenses are used in several applications and scenarios, as noted below.

  • • Used in thermal imaging cameras for security applications to detect temperature differences in passengers and luggage
  • • Used in trail cameras for night vision and to capture wildlife activity
  • • Used in infrared cameras to capture unique artistic images
  • • Used in IR cameras by inspection and home repair professionals to detect leaks and potential dangers in buildings
  • • Used in thermal imaging cameras that are connected to phones via Bluetooth to see through obstacles
  • • Used in IR cameras for surveillance and security to detect intruders or predators in invisible light and restricted areas
  • • Used in IR cameras to detect fire images by firefighters and to see people located inside burning houses
  • • Used in thermal imaging cameras to help veterinary and medical professionals detect illness and injury
  • • Used in IR cameras by electricians and engineers to detect active wires that can be a danger during construction or home repairs
  • • Helps detect heat loss in buildings and evaluate the building sustainability, integrity and isolation quality


In closing, infrared cameras use IR lenses that are sensitive to infrared heat or energy. Infrared lenses have various advantages, including the ability to capture images that are invisible to the human eye. IR lenses are also not limited by high temperatures and are also suitable for long-distance illumination. Due to their unique advantages, IR lenses can be used in several applications, including surveillance cameras, thermal imaging cameras, and infrared photography.


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