Digital infrared photography is far more convenient and practical than film-based infrared shooting, but it remains technically challenging. By understanding exposure and white balance, hot-spots, backfocus, and sharpness, you’ll avoid frustrating trial and error and quickly begin to enjoy excellent results. I’ve been shooting digital infrared for half a decade now, and those years of experience have taught me a great deal. In this article, I share my key discoveries that make shooting digital infrared images a productive and satisfying effort. A follow-up article will delve into post-processing techniques.
Infrared is the spectral band beyond deep red, starting at around 700 nanometers (visible light runs from 400-700nm) A previous PT article (May/June 2005) covered converting digital cameras for infrared; the conversion removes the infrared-blocking glass over the digital sensor and then substitutes one that passes infrared (and blocks visible light), either over the sensor itself, or by using a filter over the lens. A few cameras (such as the Nikon D2H and Leica M8) incorporate anemic infrared-blocking sensor-cover glass, and can be used in their unmodified state using filtration over the lens; the B+W 092 filter is recommended for such use. This article discusses shooting infrared images once you have an infrared-capable camera (and may help persuade you to convert a camera, if you haven’t already).
Setting expectations for infrared
1. Plan on being thrilled with some images and disappointed with others. And remember that compelling form and structure masked by harsh visible light and/or the distraction of color can be revealed in infrared. Experiment!
2. Plan on dedicating a camera for infrared use (camera modification). Using screw-on filters on an unmodified camera does work, but with inferior results at much slower shutter speeds. You will be discouraged from freely exploring infrared in varied shooting situations, due to the tedium of compos- ing and exposing as compared with free- form handheld shooting.
3. Plan on your share of “soft” (unsharp) images—accurate focus requires more effort than with visible light. Backfocus is a frequent problem. Infrared images can be as sharp as color images, but accurate focus is critical—autofocus is error-prone with most lenses.
4. Plan on paying more attention to correct exposure—cameras are not designed to meter infrared. Experience and patience are required to learn optimal exposures.
5. Plan on shooting in Raw if your camera offers it. Infrared images can often benefit from substantial adjustments (especially white balance); these are best converted in 16-bit mode from a Raw file.
6. Plan on using an image editor (e.g., Photoshop) to optimize your infrared images. Almost every infrared image can benefit from some adjustment.
7. Plan on lens purchase(s)—one or more of your favorite lenses might not perform optimally in infrared, might have unacceptable hot spots, and so on. You might have to use specific lenses to achieve top-quality results in infrared.