Ever seen those eerie looking photographs that look like regular black and white shots, but something just isn’t quite right? Or have you looked at Ansel Adams’ work before and wondered how he managed to capture such surreal and super contrasted photos? Welcome to the strange world of Infrared Photography.
Infrared (IR) photography is the same as regular photography except for the fact that it doesn’t record visible light, it records invisible light in the near-infrared spectrum (as opposed to the far-infrared portion of the spectrum which only applies to thermal imaging). The rules regarding this type of photography are fairly similar to those for visible light with a few exceptions or adjustments.
The only way to capture light in the infrared spectrum is to use special infrared film or a digital camera that is sensitive to this kind of light. Most digital cameras these days are actually sensitive to infrared light, though they usually have small infrared blocking pieces of glass directly in front of the sensor to help the camera correctly expose and focus images in the visible spectrum. Even though this piece of glass blocks most of the infrared light, with longer exposure settings it is possible to take infrared photos with the aid of special filters that block out visible light and allow only infrared light to enter the camera. There are a variety of infrared filters on the market, all with different opacities. One of the more common filters used is the Hoya R72. This comes in lots of different filter thread sizes, and I’ve tested it on the original Rebel, and the 20D with pretty good results. There are others out there, and they usually run between $50-$85, depending on the brand and the opacity.
To test and see whether your digital camera is sensitive to infrared light try this simple technique. Take any remote control and point it at the lens of your camera. Push a button and then quickly take a photo of the end of the remote. If the picture you see has what looks like a flashing light on the end of the remote you’ve got an IR sensitive camera. When shooting infrared photos with a camera that has the blocking filter in front of the sensor the two biggest factors that will change your shooting is the extremely long shutter speeds (usually from 4-30 seconds) and the focal distance adjustment. After getting the necessary filter you’ll need a tripod and a way to click the shutter without touching the camera (which would introduce vibration and blurry photos at such long shutter speeds).
As for the focal distance adjustment, the problem here is that infrared light requires a slightly shorter focal range than regular visible light. Usually, to focus you simply point the camera at the subject and press the shutter button. Not so with infrared photos. Since you’ll be using a filter that blocks all visible light the camera will have no way to “see” anything to focus on. So you actually have to prefocus the camera, put the infrared filter on, then make a minor adjustment for the infrared focal distance. This variation is sometimes accounted for on DSLR lenses where you see the focal range meter in a little window on the lens. In this window you’ll also sometimes see a little red line underneath the main black, numbered meter line. This red line has the adjustment points to move the focusing ring on the lens to once you think you have the subject in focus without the filter on. There are always more technical discussions on how to shoot Infrared, and this is hardly an exhaustive treatment of the topic. But with these basics the rest can just be tried and experimented with. Soon you’ll be showing your friends images of dark skies and “snow” covered trees in the middle of summer fields. A whole new world of photography can open up to you, just by blocking out a little of the visible light we usually strive to capture.
