ZLID IR Illumination vs Thermal Imaging comparison

Night Vision Technologies for Long‑Range Surveillance

Most cameras use visible light to create an image, when there is no available light, it creates a problem for standard imaging. There are a few different ways to capture images in the absence of available light. Infiniti Electro-Optics specializes in several different night vision technologies. The most common methods for nighttime surveillance are IR illumination and thermal imaging. Other methods include light intensification and non-imaging technologies such as radar. Note that each method has specific advantages as well as certain drawbacks, which is why we build most of our custom camera systems with multiple technologies for a more comprehensive and versatile surveillance solution.


IR Illumination

Thermal radiation

Thermal Imaging

ZLID, Thermal, SWIR



White Spotlight

Thermal Infrared Imaging

Thermal imaging uses naturally radiated heat to create an image of the scene. Everything on earth either radiates heat or reflects radiated heat, and thermal imaging sensors and lenses can pick up that heat and turn it into a viewable image.


  • No illumination needed, which means it’s eye-safe and not limited to any distance.
  • More covert than IR illumination as there is no visible red dot at the light source or visible beam if using infrared imaging technology.
  • Low power


  • More expensive than IR illumination, requires a separate sensor and lens.
  • Lower resolution than the sensors used for NIR imaging.
  • Some things designed for visible recognition may be unreadable, like printed images and lettering.
  • Unable to see through glass.

Infrared (IR) Illumination

Infrared illumination uses a beam of invisible near-infrared (NIR) light to illuminate your subject. Because the wavelength of infrared light is outside that of human vision, this is a covert way to illuminate a scene in complete darkness.


  • Relatively inexpensive, uses the same lenses and sensors already being used for color images.
  • High detail, uses the same high-resolution sensors being used for color images.


  • Distance is limited to power of infrared beam, distances longer than 5km are not feasible.
  • Illuminator is not completely covert (faint red glow can typically be seen at the source).
  • More powerful illuminators (required for longer distances of 250m–5km) can be potentially harmful to human eyes.