By Wayne Cosshall

My newest passion in photography is infrared (IR) photography, which uses that part of the light spectrum just beyond the visible red end. Digital makes it possible to experiment with IR photography in ways that film never could.

Traditionally, to do infrared photography you had to use special film with an extended sensitivity in the infrared region of the spectrum. I never really liked film IR because of issues such as getting the exposure right, trying to envision how the image would look, and the simple hassle of loading the camera in subdued light. (Maybe I just never did enough of film IR photography to get past these issues.)

Digital photography has changed that. All digital image sensors are sensitive to both the visible and near-infrared parts of the light spectrum. But in their quest for greater color accuracy, camera makers have built increasingly stronger IR-blocking filters into their cameras. None of these filters is completely effective because at least some IR light still gets through to the sensor.

When I started testing digital cameras 10 years ago for their IR capabilities, I discovered that if you wanted to shoot with only the IR part of spectrum, you had to cover the lens with what was commonly called an IR filter. It was actually a filter that blocked all visible light. The results were surprising and have remained so. As the camera’s built-in IR blocking filters have become stronger the exposure times have become longer, but quality IR images are still possible.

For the past three years, I’ve been using various digital cameras to shoot infrared in a serious way. Of course the viewfinder has been blacked out by the visible light blocking filter (usually a Hoya R72 in my case) and I have needed to mount the camera to a tripod to deal with long exposures in the 8 to 30 seconds range.

Rather than seeing these limitations as disadvantages, I have viewed them as advantages. I’ve been slowing down, exploring blurred motion, and learning to visualize the framing of my various lenses. This is all good.

Because of my growing love for digital IR, I have had a camera converted into an IR-only camera by removing the built-in IR-blocking filter and replacing it with a visible-light-blocking filter. Some people do this themselves and it works great. I chose to let someone else make this modification for me. It gives me back fast exposure times and a viewfinder I can use. Now I can shoot people, freeze motion and do precise in-camera composition, all in infrared. I love it.

Here's an IR image I shot with a long exposure on my unconverted digital camera with a filter that blocks all visible light from reaching the sensor.

This image was shot with my converted, IR-only camera.



I still use both my converted camera and my unconverted one. With my unconverted camera, I get strongly colored images. I typically convert these images to monochrome. My converted IR-only camera gives me images with much more subtle color. And I can print all of these images on a range of papers on my HP Designjet Z3100.

The end result is that it’s now really easy to take all sorts of images—almost anything I can envision. And that is what photography is all about, isn’t it?