If you’re in the market for a camera to use in your paranormal pursuits, you will undoubtedly see that your choices include thermal imaging, night vision, and infrared technology. So what’s the difference? Which is best?
What is an Infrared Camera?
IR stands for Infrared. Infrared waves comprise the part of the light spectrum which is mostly unseeable by the human eye. The same is not true for a camera. Camera sensors DO pick up infrared waves, so camera manufacturers typically build in a filter to block the IR part of the light spectrum. They do this because IR washes out the colors in photographs, and most people want the subjects in their photos to look as they do to the human eye. Infrared cameras are cameras without this modification.
Why do Paranormal Investigators Like IR so much?
As photography evolved, and IR photography became accessible to the public, investigators were intrigued by being able to see “more” of the world than they could with the human eye. There are no studies I know of that compare paranormal IR photo anomalies to visible-spectrum photo anomalies, but it stands to reason that seeing a bit more of the light spectrum will yield more data.
Is Infrared the same thing as Thermal Radiation (Heat)?
No. This is a major source of confusion. It is important to keep in mind that light is comprised of both a waves AND particles. Light will act as a particle in some instances, and as a wave in other instances. People use the term “photons” interchangeably with “light”, because they are a package deal. A photon is a quantum particle which is the carrier for electromagnetic force (light). Light itself does not have mass, so the photon acts as a temporary vehicle to move it from one place to another.
When an object has a temperature greater than absolute zero (for whatever cause), its molecules and atoms are in constant motion. The warmer the object, the more excited the molecular and atomic particles are. Warmer objects give off energy in the form of photons (light particles) which are absorbed by cooler (less excited) objects around them. Cooler object absorbs the photons and their temperature and energy increases.
Most (not all) of these photons radiate to and from objects along the infrared spectrum. However, if an object is extremely hot (like a star, for example), photons will emit on even higher frequency lightwaves, like microwaves or radio waves.
On the surface of Earth, at far lower temperatures than the surface of the Sun, some thermal radiation consists of infrared in the mid-infrared region, much longer than in sunlight. However, black-body, or thermal, radiation is continuous: it gives off radiation at all wavelengths. Of these natural thermal radiation processes, only lightning, lava, and natural fires are hot enough to naturally produce visible energy.
How the eye and various cameras work
Our eyes see light reflected off objects and the brain interprets that reflection into an image. Regular cameras, night vision devices, and the human eye all work on this same basic principle: visible light energy hits something and bounces off it, a detector then receives it and turns it into an image. If there is not light, there is no image.
The quality of a camera’s image depends on both the amount of reflected light it receives and the subject’s contrast with its surroundings. Just like your eyes see objects best when they “stand out” from their surroundings, a photographic image of a subject with high contrast (i.e. a black object on a white background) will be much easier to discern in the light, because at night, the lack of sunlight decreases image contrast, so another light source must be introduced to create contrast.
This is true for eyeballs, everyday cameras, Night Vision, and Infrared (IR) cameras. (Note: When photographing a subject with an IR camera, if there is no natural light, a light source which includes at least some infrared light is required to illuminate the subject and create contrast.) It is not true for thermal cameras, however, which require no light at all.
Thermal (or Black Body radiation) Cameras (i.e. FLIR)
There are many thermal camera manufacturers, but FLIR is probably the most well known. FLIR means Forward-looking infrared. FLIR cameras make pictures from measuring the heat every object emits rather than from visible light bouncing off an object like traditional cameras (and your eyes) do. Thermal imaging cameras measure heat in any part of the IR spectrum, from near infrared to far infrared. There is absolutely no measurement of light involved.
Thermal imagers are passive receivers, and only sense temperature and map the differences in heat to create an image. These heat signatures – usually black (cold) and white (hot) – are then displayed on a monitor. Colored Thermal devices (see below) interpret the black, white, and shades of gray into more intuitive colors, like red for warm and blue for cold. It’s worth noting that like light, heat can bounce off a shiny surface resulting in a reflection of the heat source, so be careful with your interpretation of anomalies when using thermal.
Now, this may or may not be, but it is a good example of how thermal imaging should work in a paranormal investigation. https://www.youtube.com/watch?v=_FAmQYbyT7
Night Vision Cameras
Before advanced thermal imaging and infrared illumination were developed, NVG (Night Vision Goggles) or NVT (Night Vision Technology) were the best tools we had. Night Vision technology requires there to be at least a small amount of ambient light to work. Night vision devices gather existing ambient light (starlight, moonlight, plus infrared light) through the front lens. The photons which comprise the light go into a photocathode tube that changes them into electrons.. These electrons are then amplified to a much greater number through an electro-chemical process. The electrons are then hurled against a phosphorus screen that then changes the amplified electrons back into photons in visible light that you see through the eyepiece or photo. The resulting image will now be a clear green-hued amplified re-creation of the scene you were observing.
Almost all infrared photography measures photons in both near and short wavelength infrared spectrum. Near and Short infrared is sometimes referred to as infrared. When illuminated, some photons in the infrared spectrum bounce off the subject and reflect back to the camera to generate an image. As noted earlier, the camera must not have the coating on its lens which blocks the IR spectrum in most cameras. See the end of the article to quickly test your camera for IR compatibility.
Cameras sold as Infrared will have special filters built in which confine light they receive back to a particular part of the Infrared spectrum. You can also add filters to further limit your images to only contain specific wavelengths in the infrared spectrum.
So which one is the best?
Well, of course that depends on the environment in which you are photographing, and your experimental goal. And how much money you are willing to shell out. All three options can yield amazing images. Some people don’t like the green hue in Night Vision, or they want to shoot in complete darkness, so they should opt for Thermal or Infrared instead.
High quality Thermal Imaging can give you clear results in pitch-black, but the technology is prohibitively expensive for many people. Lower priced thermal imaging devices tend to result in blotchy images with little detail, because they don’t pick up as many temperature signals as the expensive cameras do. If you are just looking for a heat distinction, however, a low-cost thermal device may work for you.
Active IR cameras are a personal favorite because they can also work in pitch-black conditions, tend to have more modest pricing, and can give amazingly crisp results which look similar to black and white photographs. They also provide more customization options, as you can add your own filters to fine-tune the spectrum you photograph.
Is my camera IR compatible?
Here’s the easy test
Take a remote control. Look at the end that points to the TV (or VCR etc), and you’ll see a little bulb or flat back plastic window. This is the transmitter that sends the signal from the remote to your device. That signal usually uses infrared light.
When you look at the remote, you can’t see anything with the naked eye when you press the buttons. But try looking through your camera! If your camera does not have the IR blocking, you’ll be able to see light when you press a button on the remote.
If you have a point & shoot camera, look through your LCD viewer while pressing any button on the remote. If your camera has you can use that to look for the light. If you have a Digital Single Lens Reflex camera you’ll have to take a photo to see the results.
For some tips on IR photography visit the link at Digitalphotographyschool.com at https://bit.ly/2MndWGa
For more about Infrared wavelengths go to https://go.nasa.gov/39f2dT2