The classic look of an infrared image is high contrast black and white, with pale vegetation, dark skies and a ghostly glow to the highlights. This was one of the techniques that every film photographer tried out at some point, and it was all about using rolls of dedicated infrared film combined with a specialist IR filter over the lens. With the arrival of the DSLR revolution you could be forgiven for thinking that the process had very much gone on the back burner, but this would be very far from the case.
In fact it’s easier than ever to master IR techniques using a digital camera, since both CMOS and CCD sensors are very good at detecting infrared light – a little too good in fact Infrared light travels at higher wavelengths than visible light which means it focuses at a different point and creates a blurred edge to all details in digital images. To combat this, digital cameras all have infrared blocking filters over the sensors. The good news is the blocking filters aren’t 100 per cent effective, so if you use a filter that blocks out visible light and allows the passage of infrared you can get some decent results. The downside of using one filter to foil another filter is that there is so little light actually making it to the sensor that slow shutter speeds are unavoidable. Despite this potential drawback, every DSLR I have tested has been able to photograph infrared light to one degree or another. Some have more effective infrared blocking filters than others, which is key to infrared sensitivity, but I will go through the results of my testing a little later. Getting started in infrared photography is all about experimentation because the techniques required differ so greatly from normal photography using visible light wavelengths. The whole process, from lighting, composure, focusing, depth-of-field, colour saturation and image editing, can be so very difficult to perfect, but I find it all worthwhile when I look at the results. The pictures have a surreal quality that people tend to either love or hate… personally I love it.
What you need: Infrared filters and kit
The first and foremost requirement is an infrared filter. A number of filter manufacturers offer an infrared option, although many retailers may have to order them in as they are niche interest items. Holding an infrared filter up to the light, it appears to be black, which is a reminder that it is blocking the transmission of visible light. Some filters block light wavelengths at different thresholds, with some very expensive examples blocking all but the very highest wavelengths of light. For £20 to 35 you can pick up excellent filters from manufacturers such as Hoya, Lee and Tiffen.
The screw-fit Hoya R72 is probably the most easily available, though costing around £30 and upwards depending on the filter size it can be quite costly for casual experimentation. It is in my opinion an excellent filter for infrared and is never absent from my camera bag. The ‘87’ rated gel filter from Lee is also widely available and, costing around £15, is considerably cheaper than the Hoya. The Lee 87 filter has a higher cut off threshold for light transmission which means you get a stronger infrared effect. However, the darker filter also requires longer exposures than the Hoya to yield results. The downside of the gel filters is their vulnerability to scratching, bending, folding and, occasionally – given ultra long exposures – light seeping in behind the filter, giving a disastrous white haze across your image.
The correct method of using gel filters is to slot them into filter holders which can be relatively pricey, although I have heard of penny-pinching photographers cutting a disc from the infrared filter and sandwiching it between two UV filters. If treated with care and used correctly however, the Lee 87 filter produces stronger, more contrasting infrared images than the Hoya R72, although the screw- in format of the Hoya makes it far easier to use for ad-hoc subjects. A tripod is essential for infrared photography due to the long exposure times. Also, if you want to avoid camera shake from firing the shutter, a remote shutter release is a good idea.
If you just stick an infrared filter on your lens and take a picture, the image will be totally saturated in red. This is what the camera derives from the light making it through to the sensor, with the automatic white balance completely unable to cope. For me, these red-washed images are rarely of any interest in their unedited state as it is generally the classic infrared black and white look I am after. To get this I either de-saturate the image in Photoshop before whacking up the contrast or preferably I use a custom white balance when taking the shot. By defining a custom white balance with the infrared filter in place, the camera shifts its colour handling way up into the green end of the spectrum, cancelling out the red to leave a black and white image. The same effect can also be achieved by shooting in RAW and adjusting the white balance later.
Some cameras, such as Nikon’s D40 and D80, aren’t especially good at taking custom white balance images with an infrared filter over the lens (the test picture gets rejected by the camera for some reason), so for these cameras a good compromise is to select either the warmest colour temperature (2500K on the D80) or tungsten white balance. Both these options are enough to take the edge off the red saturation and bring some blacks and whites into the image. An interesting by-product of the digital processing within the camera is the production of false colours when shooting infrared. These colours aren’t immediately obvious when looking at the basic red saturated infrared images, but if you play around with the levels settings in Photoshop (actually Auto-levels usually does the trick) the false colours suddenly pop out of the reds. Some vegetation appears in pale blues and purples, skies can sometimes go yellow, mud turns red. It all sounds ridiculous but the images themselves can be quite striking. I’ve read that infrared light is strictly monochrome, so these false colours I assume are generated by the camera’s image processing. The false colours also appear in infrared images shot with a custom white balance, though they tend to be more subtle than those from the red saturated Auto-white balance shots. Predicting what objects will look like when shot in infrared is an art in itself, and I still get surprised at how images appear when I get them home and onto the computer.
Technique: Landscapes and buildings
Nine times out of ten, infrared photos you come across in exhibitions or on the web are landscapes. This is the bread and butter of infrared photography, where focal length is less of a concern and long exposures are fine as the subjects are static. As I mentioned earlier, infrared light focuses at a different distance to visible light. You can’t manually set the focus before attaching the infrared filter as this will produce blurred pictures. Fortunately, the autofocus feature of all DSLRs seems to cope well, although you have to have faith in exactly what the camera is focusing on. However, for big targets like landscapes the autofocus is generally reliable.
Along with a shift in the point of focus, infrared light also tends to push aperture requirements down a notch. Essentially the depth of field you would expect from setting an aperture of f/5.6 can be achieved at f/4.0: it’s quite a subtle difference but it’s one that it’s worth being aware of. A major draw for photographers experimenting with infrared is the way skies are reproduced. Even with just moderate sunlight the usually blue parts of the sky appear very dark and even the whispiest of clouds appear bright. Clearly the water vapour in clouds is highly reflective of infrared. This means you can get big punchy skies on average-looking days. Also, where long exposures are used you are able to pick up the movement of the clouds, which if done right can give a fantastically moody feel to a picture shot in broad daylight.
An advantage of infrared over visible light is its ability to penetrate haze. Because of this you can get surprisingly clear landscapes where, to the eye, a mist is obscuring details in the distance. In general it is organic subject matter that reflects and absorbs infrared light in funky ways, so when shooting entirely man-made subjects such as cityscapes there is little to set the images apart from standard black and whites. For this reason I tend to compose these kinds of shots with a lot of sky to give some scope for the infrared to show itself.
Technique: Portraits and wildlife
These are particularly tricky subjects for infrared. Along with the difficulties of focusing, you have the natural movement of the subject to contend with. For this reason, you can’t rely on hugely long exposures and you will need to find a way of bringing the shutter speed way down. You can of course up the sensitivity, although even at ISO 1600, most DSLRs still require shutter speeds of over a second. However, there are a handful of cameras that are especially sensitive to infrared light that can take shots at fractions of a second with low ISO settings. I will go into more detail about these cameras later, but suffice to say that without one of these cameras portrait and wildlife photography is largely excluded from the repertoire of infrared photographers. However, portraiture in infrared can be especially striking as skin takes on a porcelain-like quality. Also, depending on how the light falls on them, eyes can be either very dark or take on a slightly albino look. Another quirk of shooting in infrared is that clothes tend to come out pale or white, even if they are black in real life.