Early this summer, I started a new project: infrared photography. “What is it?”, I hear you cry. Infrared (or IR) photography is something you can accomplish to varying levels of success with any digital camera. The two ways I know of are either using a modified camera, with its IR blocking filter removed, an expensive process, which usually renders the camera useless for anything else, or the method I use, which involves mounting an infra-red sensitive filter, like the popular Hoya R72 (In Japan, branded Kenko), which will block out all the visual light below, say, the 720 spectrum. What remains, after a relatively long exposure, is what can be seen with infrared light only, perhaps with some visual light bleeding in, giving a touch of colour.
Stronger filters, such as a 830nm, or even 920nm one are more expensive and on unmodified cameras lead to exposure times 2-3x longer, meaning perhaps as long as 30 minutes and so impractically long. Seeing as anything stronger than 720nm tends to block out all visual light, you are left with a very contrasty, black and white image that is itself very impressive, but maybe not as interesting as the ‘false color’ images that comparatively lighter filters can give.
A false colour image, as opposed to black and white, taken with automatic white balance, will just be full of red hues. By making a custom white balance, based on setting the white point on green foliage, preferably grass in sunlight, will help things along a bit, giving the more desirable white foliage and blue or brown skies that most people prefer for these false colours. The false colours themselves, by the way, are really a means of aesthetic colour separation, much as you may see on NASA photos of space, with different bands of heat coloured differently. Having played around with them a bit, I must concur that dark buildings or tree trunks and bright white leaves and grasses, set against either a blue or golden sky looks best and brings out a ‘wow’ sensation that combinations leaving in reds and pinks fail to elicit.
Yet even the custom white balance isn’t quite enough alone. For one thing, most raw converters won’t go down into the ‘deep blues’ of below 2000hz, so unless it’s a jpg, you generally end up with a red-hues raw file. I export that into Photoshop and then do what is called a channel swap, where you reverse the blue and red channels. To speed things up, I use this action, available (at least for now) for free online- I then tweak the hue settings at the end of the action to get those blue skies, then play around with levels to increase the contrast.
Taking the photo is a lot more difficult than you might imagine…
Taking the photo is a lot more difficult than you might imagine. I’ve found my way around HDR work, which newer technologies have made a lot easier, but this is a real challenge and a half! Once the filter is on the lens, having blocked out visible light, the viewfinder is black, so a camera with live view is better. Yet the filter is extremely dark, so with a dark lens, even live view might black out, depending on how sensitive to IR light the camera is. I found my D5100 very dark nand needing much longer exposure times than my Olympus EPL-2. The latter can generally see a bright enough image through live-view and autofocus the lens that way. With the Nikon I need to focus before I put on the filter, which sounds fine, except for one little caveat… lenses focus at different points in infrared light, so I need to play around with it manually until it hits an infrared infinity position, slightly different from the usual one (I generally use this camera at infinity for this). It helps to also stop down the lens a bit to increase the depth of field for this, making more chance of a sharp image.
For some reason, perhaps related to the greater sensitivity to infrared light, there isn’t much colour in the Olympus’ images, being mostly black and white with hints of brown or gold, very rarely blue. Meanwhile, despite the massive exposure times, which can be as much as 7 minutes, the D5100 captures some amazing false colour, making for exotic and remarkable images, like these. So whilst the Olympus can even be used hand-held at times and is much more convenient to focus, I can get a very different result through the Nikon and of course, with the larger sensor, a richer image, with far more dynamic range and also more detail.
One more thing to watch out for is lens ‘hot spots’. This, more commonly on newer lenses with special anti-reflective coating, results in a bright spot in the middle of the image in infrared photography. Here is a list of good and bad lenses for this, which might surprise you, as some kit zooms are very good for infrared, whereas expensive pro models, such as my Nikon 17-55 f/2.8 AF-S have the dreaded hotspot, if not all the time, enough to rule them out. Luckily, my Olympus lenses are all fine in this regard. Of the ones I’ve used on Nikon, the 18-55mm VR kit zoom is fine, as is my Sigma 50mm f/1.4 HSM, which while a little long, is such an excellent lens I like to use it for artistic photography whenever I can… though I’ll be trying out others when I get around to it.
A view of another world, one we’ve been living in all the time.
It may be a lot of trouble, but it brings a view of another world, one we’ve been living in all the time. Some incredible images are possible this way and since so few people have ever used this technique, especially the false-colour mode which is specific to digital (though there was a false-colour infrared film made by Kodak, which had its own special look), you are assured of unique images wherever you go. They have an ethereal, spiritual quality to them and their exotic look gives a sense of timelessness and otherworldliness. I liken to think of them as a magical dimension of our world, one we rarely see, but can be revealed this way, in many cases for the first time.
Perhaps one day I’ll get or convert a camera specially for infrared work, preferably a live-view capable DSLR. Until then, I’m quite happy to experiment with the filter and play around with the images, to find out just what is possible to see.