Welcome to the World of Invisible Light

Today’s Post by Joe Farace

Astronomers have long used the infrared spectrum for astrophotography of distant non-terrestrial subjects but there are plenty of terrestrial applications for infrared photography too, including forensic investigation and aerial crop or forest surveys.

My personal philosophy is that photography should be fun. Part of having fun is trying new things. Digital infrared photography is lots of fun because it helps you look at your world in a new way and lets you create images that look unlike any other technique you’re likely to try. That alone is a good enough reason to try infrared digital photography.

 

Every photographer knows about the visible light but there are other kinds of light that we can’t see. What you see as red, orange, yellow, green, blue, indigo, and violet are different waves of light. Shorter waves are blue and the longer ones appear red to our eyes. Every color’s wavelength is measured in nanometers or one billionth of a millimeter or microns that are a millionth of a meter. Red light begins at wavelengths of about 0.65 microns. Violet light has wavelengths around 0.4 microns and yellow light waves are 0.6 microns. Your eyes can’t see light with a wavelength longer than 0.7 microns. We also experience thermal infrared light when we feel the sun’s heat of the on our skin.

UV Light and Filters: Ultra Violet light comes from the Sun but the Earth’s ozone layer protects us from most of this light but that doesn’t mean you don’t need a UV filter on your camera. While many photographers keep UV aka Haze filters on all their lenses as protection, UV filters reduce the amount of ultraviolet radiation striking the image sensor or film and suppress atmospheric haze or dust. When photographing at high altitudes of 14,000 feet or more, you need a capable ultra-violet (UV) filter in front of your lens to approximate the same color correct view that your brain send to your eyes.

For my personal photography, I consider light with wavelengths from 700 and 900nm to be infrared light and this band of infrared light is a thousand times wider than that of visible light yet is completely invisible to our eyes. Infrared film and some video cameras are sensitive to what is called near infrared. This is also the type of IR light that your television remote control for uses. (For a link to using the old TV remote test for your camera’s IR sensitivity click—here.)

I try to write a post about infrared photography at least once a week, so if this topic interests you check back from time to time.

IR.book

Life Pixel does a great job with IR conversions and they have done all of the recent conversions for my Canon DSLRs as well as Panasonic Lumix G-series cameras, including the Lumix G6 used to make the above image. Lens was G Vario 12-32mm f/3.5-5.6 with an exposure of 1/640 sec at f/11 and ISO 400.

My book, “The Complete Guide to Digital Infrared Photography,” is out-of-print but new copies are available from Amazon for $36.21 and used copies for $14.68, as I write this. Creative Digital Monochrome Effects has a chapter on IR photography and is available from Amazon with used copies selling for $4.00, a price that can’t be beat for one of my personally favorite books.