The word photography brings images to mind … happy families at scenic vistas with their point-and-shoots, a dozen or so tripods with retirees behind them surrounding a snowy owl, folks out before dawn with lenses pointed towards the sunrise. One common factor – visible light. American photographer Joel Sartore has said: “If I can see it I can shoot it.” Okay … but how about using light you can’t see?
You know how it works. The human eye gathers light and sends it to the brain for interpretation. Your perception of a scene is based on what the brain perceives in terms of color, tonal range, highlights and shadows.
Light, as we normally think of it, is a small part of the electromagnetic (EM) spectrum. The EM spectrum covers everything from long radio waves (EM waves that are meters long) to gamma rays (the longer gamma rays are around one trillionth of a meter long). Visible light is in the middle somewhere, with red light having the longest wavelength, violet the shortest. Infrared (IR) light is EM radiation with a range of wavelengths just below visible red light. It is light you can not see.
How is IR different in photography? What you can capture with a conventional DSLR camera is called “near IR”, which means it is reflected EM, not EM radiated by a hot body. A cloudless sky is transparent to IR, so is a still body of water. Chlorophyll reflects near IR almost 100%, everything else in the landscape to a lesser degree. There’s no red-green-blue … the world becomes black and white … but not the black and white you’ll get with visible light, and not a negative of it either.
The two ways I’ve taken IR images are with filters and with a converted camera. A 720 nm filter will allow only IR into your camera. This is the least expensive option; what you give up is handheld shooting. A 720 nm filter acts like a 12 stop ND filter, meaning a 1/60 second shutter becomes a 64 second shutter with the IR filter. A converted camera has had the “hot filter” installed by the manufacturer removed (allows IR into the camera) and a 720 nm filter added (blocks visible light from entering the camera) … the result … being able to shoot IR with fast shutter speeds (no tripod!).
Best time to be out for IR photography is a bright, sunny day … while the visible light shooters are waiting for the golden hour to arrive. Bright sunshine means lots of IR to take in, giving you shorter shutter speeds and higher contrast in your photos.
The world in IR is a different world, and a beautiful one. And as much as you might anticipate what an image will look like, there’s always a level of uncertainty because you are using light you can’t see. But it is fun and always worth the effort.
There’s a lot more to IR photography, so maybe another post another day. Until then I hope what I’ve provided here will help you get started, if you are so inclined. Should you have questions, please don’t hesitate to ask.
Be well and stay safe.
Gordon
If you'd like to view more of Gordon's work, click here.