Ultraviolet UFO Photography
At the opposite end of the visible light spectrum and just beyond the colour violet, we have the ultraviolet. Like infrared, ultraviolet light is also invisible to normal human sight, but by using a full spectrum camera or camcorder in conjunction with an ultraviolet pass filter you can take a glimpse into this normally unseen world and record the strange invisible life-forms and objects that reside there. In his later work Trevor James Constable also began probing the ultraviolet, his filter of choice being the Wratten 18A, and in 1975 he discovered that he could capture UFOs from the window of an airliner by placing an 18A filter over the lens of a low-light Super 8mm movie camera loaded with Ektachrome 160 colour film. The 18A filter is designed to block the visible light spectrum while passing its two invisible ends i.e. the infrared and ultraviolet, but despite this Constable managed to capture the UFOs in full colour as they flew alongside the airliner at 30,000 feet. He realised that these colours were created between the lens and the camera filter, and he called this mingling of the two invisible ends the reverse or dark spectrum.
MaxMax have a range of ultraviolet pass filters available including the X-Nite 330 and the X-Nite UVR, both of which I have used during my photographic pursuit of invisible UFOs. The X-Nite 330 blocks the visible light spectrum while allowing the invisible ultraviolet radiation to pass to the camera's sensors, having a peak ultraviolet transmission of 80% at 330nm. It also has a slight infrared transmission around 720nm, whereas the X-Nite 330C by comparison has barely any noticeable infrared transmission, giving you a pure ultraviolet image. The X-Nite UVR filter is predominantly an ultraviolet pass filter that blocks most of the visible light spectrum apart from a small amount of visible blue light, and like the X-Nite 330 it also has an infrared transmission, but ultimately it passes a larger amount, having almost a 60% infrared transmission at 720nm.
After much experimentation I discovered that the X-Nite 330nm filter performed best for my needs when used in combination with the "sun obliteration technique," and much of my best ultraviolet UFO footage was obtained this way. Because it is such a dark dense filter I found the X-Nite 330nm to be much more efficient when used in bright sunny situations with lots of ultraviolet light in the scene, and it didn't perform that well on dark or overcast days when there is little or no natural sunlight. Due to the X-Nite UVR filter passing both infrared and ultraviolet radiation along with a small amount of visible light, the sheer amount of reflected light would often be too intense for the camcorder's sensors, sometimes causing distorted or over-exposed images. For this reason I find the X-Nite UVR is much more suitable for filming things further away or much higher up in the sky, rather than employing the filter in any type of sun obliteration.
Fig: 1. My first convincing capture in the ultraviolet was this jellyfish-like invisible life-form, filmed as it moved "tentacles" first above the main roof of my house on the afternoon of September 29th 2011. The object was captured using a full spectrum Sony Handycam, which was fitted with an X-Nite 330nm UV pass filter. The "sun obliteration technique" was employed, with the apex of the house roof being utilised to block out the main body of the sun. The "jellyfish" which was recorded at 25fps only appeared in two frames, and by the next frame it had moved far enough out of the "illumination zone" that it became very faint and almost transparent and barely visible. Fig: 2 shows an inverted version of the same image.
X-Nite UV filter transmission rates. Copyright MaxMax.com.
The graph above shows the transmission rates of the X-Nite 330, 330C, and UVR ultraviolet pass filters available from MaxMax.com. The x-axis shows the infrared transmission in nanometres, while the y-axis gives the percentage of transmission. As can be seen from the graph, there is a slight differential between the ultraviolet transmission of each filter, as well as the amount of infrared radiation that is also passed.
In Figs:3 and 4 we see a perfect example of an invisible UFO entering the "illumination zone" and becoming visible in the ultraviolet part of the electromagnetic spectrum. This footage was taken on a sunny afternoon in September 2011 using a full spectrum Sony Handycam fitted with an X-Nite 330nm UV pass filter. It is advisable to keep an eye on the camcorder's LCD screen quite regularly when filming to ensure that the sun does not rise to high above the edge of the roof, as this will create a "white-out" which will ruin any potential footage and could potentially damage the camcorder's sensors. Always use the LCD screen when working, and never look directly at the sun through the camera/camcorder's eyepiece, no matter how tempting it is, as this can result in permanent eye damage.