Thermal Imaging
Far beyond the visible spectrum lies the thermal spectrum of long-wave infrared (LWIR). With wavelengths between 8,000-14,000nm, it’s wildly different to the more common near-infrared (commonly known as IR or night vision).
Is it infrared?
Everything has a temperature and therefore radiates varying levels of heat. Heat is infrared radiation; it’s the same energy we perceive as light – just at a different point on the electromagnetic spectrum.
The higher the temperature, the shorter the wavelength emitted. Objects in the long-wave infrared spectrum radiate energy that we can feel as heat, but not see as light. If an object it gets hot enough, it will begin to glow in the visible spectrum – literally red-hot.
It is this much cooler infrared radiation that thermal cameras can detect, well below the point at which they begin to glow in the near-infrared or visible spectrum. This is why it’s called long-wave infrared (LWIR).
So yes, it is infrared, but not in the context more commonly associated with the name. The term IR typically refers to near-infrared and so to differentiate, the LWIR portion of the IR spectrum is better described as thermal.
Applications
Thermal imaging is a form of night vision that can be used day or night. Traditional night vision only makes a dark scene brighter; if an animal is hidden in the foliage, it’ll still be camouflaged in its surroundings. With thermal however, it’ll glow and stand out from any environmental cover.
Beyond detecting and filming wildlife, thermal imaging can be used for lots of applications – and many of these creative uses are for filmmaking. Perhaps the most popular examples of using thermal imaging in filmmaking are Predator (1987) and Sicario (2015), though our clients have also used our thermal cameras for experimental dance pieces, music videos, and much more.
Additionally, thermal imaging can be very helpful for scientific research, from counting the amount of nesting birds to diagnosing medical conditions – or even assisting fire fighters.
Originally designed for the hunting industry, the Pulsar Helion XP50 is one of the highest quality thermal cameras available and can be used for a wide range of applications including natural history filmmaking and ecological surveys.
Is it safe?
Yes. Infrared radiation does not mean radioactive; it means it radiates heat, just like the radiators in your home.
FAQ
How do I film in thermal?
Thermal imaging works by line-of-sight; the sensor needs to be able to directly detect the person or animal you’re looking for, so if they’re hidden behind a tree trunk or other solid object, you won’t be able to see them. If the animal has been resting against something for a while however, you’ll be able to detect that object heating up – likewise if a person or animal walks through a cool environment, you can see their footprints in thermal for several seconds after they’ve passed through.
Additionally, glass blocks the wavelengths thermal cameras use – so you can’t film out of a closed window, but you might get an impressive thermal reflection which could be perfect for your project.