Welcome to the World of Invisible Light

hidden.IR.vertAstronomers 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 IR 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.

Spring.IRGeek Alert: Ultra Violet (UV) light comes from the Sun but the Earth’s ozone layer (don’t go there…) 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 your brain send to your eyes.

For the purpose of this blog and my personal photography, light with wavelengths from 700 and 900 nm will be called infrared light. This band of infrared light is a thousand times wider than that of visible light and 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. (The old TV remote test—here.)

IR.bookMy book, “The Complete Guide to Digital Infrared Photography,” is currently out-of-print but used copies are available from Amazon at bargain prices. Creative Digital Monochrome Effects is still in print and has a chapter on IR photographer. It’s available from your friendly neighborhood camera store or Amazon.

If you prefer to use a converted camera instead on on-camera filters and want to save a few days processing time when converting your camera to infrared when ordering a conversion from LifePixel, use the coupon code “farace.”

Author: Joe Farace

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