“In the beginning it was all black and white.”—Maureen O’Hara
A digital camera’s sensor typically sees light in wavelengths from approximately 350 to 1,000 nanometers. A nanometer (nm) is a metric unit of length equal to one billionth of a meter. Your eyes can see a range of light from approximately 400 to 700 nanometers.
Most digital cameras place a low pass filter in front of the sensor to lets low frequency light visible to the human eye pass through to the sensor where it’s captured and recorded but blocks unwanted light from the infrared and ultraviolet spectrums (the high end and the low end wavelengths) from polluting a photograph’s color. As owners of early Leica M8 cameras quickly discovered this piece of glass is important for maintaining maximum color fidelity.
The above image was made using a Panasonic Lumix G5 converted to IR capture by LifePixel, with the Standard IR (720nm) filter that’s equivalent to Hoya R72 Filter or Kodak Wratten 89b filter. Lens was a Lumix G VARIO 14-42mm f/3.5-5.6 (at 42mm) with an Av exposure of 1/30 sec at f/9 and ISO 400. The image file was tweaked using Google’s Silver Efex Pro.
How different companies accomplish their IR conversions varies but it usually goes something like this: They remove the camera’s external housing, then remove the internal Low-Pass Filter that prevents infrared and ultraviolet light from striking the sensor. The filter is replaced with a highest quality glass and/or quartz filter that meets the specific nanometer filtration you requested. Here’s a link to the seven options offered by LifePixel but many other companies offer similar choices.
You conversion company may request you send a lens with the body. That’s because they will adjust camera focus to make sure the camera focuses just as well as it did before the infrared conversion. I must confess I haven’t done this with the five conversions that I have done through three different companies and I’ve been happy with the focus. But that’s my choice. If you are a perfectionist you might want to go for it.
My book, The Complete Guide to Digital Infrared Photography is currently out-of-print but used copies are available from Amazon starting at $13.18, as I write this. Creative Digital Monochrome Effects has a chapter on IR photography and is available from Amazon with new copies under $10 and used copies selling for $2.55 (plus shipping) which has to be one of the best book deals out their for what is my personal favorite book.