Full Spectrum Cameras Cancel Out Wavelengths – Infrared Vs UltaViolet used in Ghost Hunting


I’ve met a lot of amazing people during my previous career as an event organizer in the camera and film industry. While creating workshops a few years back, I ran into a new instructor who was going to be teaching infrared photography. He was a scientist for a large company and infrared photography was his hobby.

This immediately gained my interest because at the time I had been watching “ghost hunting shows” for quite a bit. I had asked the instructor if he has ever found anything suspicious relating to the paranormal that he picked up on his infrared images.

We then began to discuss using “full spectrum” cameras. His response was very interesting because I remember him saying that Infrared and Ultraviolet “cancel” each other out. But this was a few years ago and I had forgotten much of the conversation.  I decided to write him recently to clarify. He has allowed me to present his explanation but would prefer to remain anonymous at this time.

Italic indicates that the text has been edited by me for clarification/definitions. 

TAZ: “I was wondering if I could interview you about infrared vs ultraviolet on the color spectrum. I remember you saying they cancel each other out and I would like to discuss further.”

MB: “Your question relates to a full spectrum converted camera. In this case the IR-blocking filter in front of the sensor is removed and only replaced by a glass plate.

Now the sensor is receptive to all wavelengths from 200-1500 nanometers (nm) wave length. 200-400 nm in UV, 400-700 nm is regular light (what our eyes can see), and above 700 nm is infrared.

Ghost hunters often claim to see ghosts best with a full spectrum converted camera. The issue here is that you get a mix of all kind of wavelengths in one photo or video stream – you might see everything but nothing!

It is much better to preselect the wavelength range which you consider most important to capture paranormal activity/ghosts. I read that those might be best seen in the UV, some claim in the infrared.

In any case you need to add filters in front of the lens to filter out the wavelengths which you don’t want to get on your sensor. So if you want to focus on the UV spectrum, you need to block everything above 400 nm. If you want infrared, you need a filter which blocks everything below 700 nm.

Full spectrum cameras might work, but as I pointed out earlier you get a big mix of wavelengths all at one which might not support clarity and interpretation of the image later.

What do you think? Leave a comment to discuss!


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