Inside an Infrared Conversion

Today’s Post by Joe Farace

A digital camera’s sensor typically sees light in wavelengths from 350 to 1,000 nanometers*. Your eyes, on the other hand, see a range of light from approximately 400 to 700 nanometers.

*A nanometer (nm) is a metric unit of length equal to one billionth of a meter.

Most digital cameras place a low pass filter in front of the sensor that allows low frequency light visible to the human eye pass through to the sensor where it’s captured but blocks light from infrared and ultraviolet spectrums (the high end and the low end wavelengths) from polluting a photograph’s color. As  early Leica M8 owners quickly discovered, this piece of glass is important for maintaining maximum color fidelity.

The above image was made using a Panasonic Lumix G5 that was converted to IR capture by LifePixel, using their 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 with 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 then replaced with a high quality glass and/or quartz filter that meets the specific nanometer filtration you requested. Here’s a link to the options offered by LifePixel but many other companies offer similar and sometimes different choices.

Your conversion company may ask you send a lens with the body so they can adjust focus to make sure the camera focuses just as well as it did before infrared conversion. I must confess I haven’t done this with the six conversions I’ve done through three different companies and I’ve been happy with the camera’s focusing. 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 out-of-print but used copies available from Amazon for $14.10 or less as I write this. Creative Digital Monochrome Effects has a chapter on IR photography and is available from Amazon with used copies a steal at just four bucks and like the IR book would make a great gift for your favorite photographer or yourself.