Determining Your Camera’s IR Sensitivity

by | Oct 1, 2018

Today’s Post by Joe Farace

These days most of the sensors used in DSLRs and mirrorless cameras are sensitive to more than just visible light, which can cause color balance problems. That’s why most manufacturers place an anti-aliasing filter in front of the imaging chip to block infrared light. This filter rejects infrared light while protecting your images from color errors and desaturation without loss of ISO speed. An anti-aliasing (or optical low-pass filter) performs these functions and also minimizes aliasing and moiré in your photographs but at the expense of sharpness, which is why more and more camera are eliminating it. The Pentax K-1 Mark II I tested for Shutterbug lacks an optical low-pass filter but includes an AA Filter Simulator function, which slightly moves the sensor to mimic the effects of a physical filter.

When cameras are reviewed in (what’s left of) photographic magazines and lots of other blogs, a camera’s infrared capability is often overlooked. While the sensors in most digital cameras are fitted with that infrared cut-off filter designed to reduce IR contamination, many cameras let enough IR through to allow at least some, what some call, near infrared photography. Here’s how to leverage that fact:

One of Farace’s Laws is that most DSLRs and mirrorless cameras (that I’ve tested) can be used with appropriate filters to capture infrared images. (I can’t speak for Sony cameras because I haven’t been able to test their infrared capabilities.) Like everything in digital imaging this is subject to change, so you’ll need to test your own camera to find out. How do you do it?

Whenever I get a new camera, I run down to the family room and give it the “remote control test” that, I think, is one of the easiest ways to see if your camera is infrared capable: You point a TV remote control at the lens and take a picture or look at the image on the LCD screen. If you see a point of light, you’re ready to make IR digital images with the appropriate filters. Caveat: Some readers have told me that this test is not infallible but it’s the only one I know short of sticking an IR filter in front of the camera’s lens and, you know, see what happens. This latter test is infallible. Tip: Maybe someone will loan you their IR filter to give it a try.

What happens if your camera fails the test and you still want to shoot IR images? The best solution, if you’re really serious about IR photography, is to convert a camera to infrared-only capture as was done with the Panasonic Lumix G5 and G6 mirrorless cameras used to make today’s featured photographs.

I have found that Life Pixel does a great job with IR conversions and they have done most of my Canon DSLRs and all of my Panasonic Lumix G-series mirrorless cameras. This is not a paid or sponsored endorsement, just my experience.

My book, The Complete Guide to Digital Infrared Photography is currently out-of-print but used copies are available from Amazon for less than twelve bucks as I write this. Creative Digital Monochrome Effects has a chapter on IR photography and is available from Amazon with used copies selling for under $2.00, less than your next coffee at Starbucks.