Please comment and correct as needed…
Not too long ago, I found myself in the market for a “full-spectrum” camera to enhance my paranormal investigation kit. This venture has instead taken me full circle to where I am less able to justify the expense on my tight budget for equipment suitable for paranormal investigation. Other than an extremely limited “live” view of the situation, a full-spectrum camera system itself adds little value to investigation efforts assuming ghostly energies are indeed loitering at the IR and UV spectrums.
Let’s look at the term “full-spectrum”; this is indeed a misnomer. We are not getting a magical view into the entire IR / UV spectrums; not even close. What is really happening here is our ability to “see” at the limits of normal vision is enhanced to a very slight degree by adding more light at the limits where our eyes are weakest. Consider the reality of what our eyes can see; if we are adding “invisible” light to the environment, any reflection of this invisible light will also still be invisible. At best, we are altering contrast to help identify shape and movement. Granted, this is a key point when ghost hunting.
What about the camera technology commercially available to most of us; what is it really? It is nothing more than a normal digital camera with IR and UV filtering removed from the light path. Yes, we pay extra to have someone remove parts from a “normal” camera; i.e. new capabilities are not being added to the camera. At the end of the light path we find a sensor as the surrogate film we derive the images from. As far as I have been able to determine, this sensor remains the same whether the camera is “full-spectrum” or not. With filtering removed or added, the camera then does its best to present a visible spectrum interpretation of what the sensor has detected. Resulting images show odd hues of color because the electronic system of the camera is designed to create images with the filtering in place. It is less common but we also find camera versions with IR / UV filtering removed and a new filter added to remove visible light from the light path. I cannot say that I have seen one of these in use; so I will not comment on results.
Where might this leave us? I believe it leaves us needing to spend much more cash than we would like to. Yes, the IR “night-vision” or “full-spectrum” cameras, at ghost gear shops everywhere, do give us a usable live view as we stumble through the darkness as well as the occasional intriguing apparition. However, I believe they are a bit gimmicky in that they do not deliver on the capability we really want them to promise us. If we really want to explore the IR end of the spectrum, we need to put thermal imaging in practice more often. Likewise, if we want to explore the UV end of the spectrum, we need to look into a true UV imaging system. To add basic capabilities at both ends of the spectrum, your ghost kit budget will need several thousand dollars US.
This post was edited by Rob ~ DEADPsalm at December 30, 2011 1:09:45 AM EST
Wes, I agree with your correction in general terms. Yes, the camera renders an image from whatever light its sensor sees. However, the circuits of the camera do interpret a mass of numbers, from the sensor, into an image. The software/firmware of the camera derives a given color on the rendered image from a given number generated by the sensor. I am suggesting a lower quality camera is less likely to have thoroughly designed software capable of dealing with IR and UV data because it is designed around a cheaper sensor with filters in place. Remove the filters and the camera may “misinterpret” the data. Perhaps my aerospace background is giving far too much credit to camera manufacturers?
I will also point out my concern with LED illuminators. LEDs are designed to emit a very specific wavelength. All of the IR or UV illuminators I have researched are utilizing a single type of IR or UV LED. A descent camera sensor will have IR wavelength sensitivity from 700 nm to 1100 nm and UV wavelength sensitivity from 150 nm to 400 (visual range is 380 nm to 750 nm). If typical IR LEDs are illuminating at 820 nm and typical UV LEDs are illuminating at 380 nm, we are completely missing the bigger picture. Yes, there will be some wavelength variation with the reflected light but we are nowhere near producing a “full spectrum” image. I have read that some teams are utilizing true white-light illuminators in an effort to get this full spectrum of light but I could not find any mention of results from this.
Yes, this is all baby step stuff. Unfortunately, I suspect most teams using this technology are falling for the gimmick rather than understanding what the technology is really providing. As Wes said, the technology needs to be used properly.
Just in case anyone is interested, here is a company that will professionally modify the filtering in digital cameras: http://www.lifepixel.com/