Inspiring Infrared
Shooting infrared is simple and you can get awesome, very stylized results as soon as you’ve conquered a few basics. However, it’s fair to say that the post-apocalyptic or deep black skies, white foliage and pale flesh tones are not a look that has universal appeal. On the other hand, the spooky style that infrared capture imparts on ordinary scenes means that it’s ideally suited to photographers searching for a more individual approach.
There are a great many technical considerations. Do you shoot on film or digital? If film, what film? If digital, which camera works and which doesn’t? What filters are needed? How do you calculate exposure? Yes, there are certainly plenty of questions that need answering.
Let’s start by going back to basics, but without making it too much of a physics lesson. In the electro-magnetic spectrum, visible light has a wavelength range of (roughly) 400-700nanometres (a nanometre is one billionth of a metre). Below 400nm is ultraviolet and above 700nm is infrared, both of which are invisible to the human eye.
There is no precise point where visible light becomes infrared but it is typically between 700nm and 800nm – according to the International Commission on Illumination, near-infrared or the IR-A section of the spectrum is 700-1400nm.
In the practice of infrared photography, it’s this area of the spectrum that we’re working with. Infrared photography in this context should not be confused with thermal imaging which requires sensitivity from 7000nm to more than 14,000nm.
There are lots of whys and wherefores in infrared photography and how you approach the technique does depend on your camera, your preferences and your post-production skills.
For a start you have the option of film or digital capture. In some respects, shooting infrared with film is easier than with an unconverted digital camera. You just load up with the appropriate film, fit a filter and off you go. That’s very simplistic, but shooting film does mean that most cameras are suitable. There are a few models that aren’t – they may leak infrared, or have infrared sensors that are used for the transport system and will fog the film, but generally any film camera will do.
If you want to shoot film, there is a limited choice in emulsions, although that has always been the case. Years ago, Kodak used to offer a colour slide infrared film called EIR and a black & white infrared film called HIE but sadly no longer. If you want to try the Kodak colour infrared slide film you had better hurry. There is a German supplier although at the time of writing, its website said availability was very limited. Visit www.tarquinius.de.
There are products from Efke, Rollei, and Ilford – the latter’s SFX 200 film is an extended red sensitivity film rather than true infrared. Efke IR820 is comparable to Kodak’s HIE’s with coarser grain and needs unloading/loading in total darkness while Rollei’s IR 400 is more like SFX200 or Konica Infrared (also defunct) with smoother grain and can be loaded/unloaded in subdued light.{pullquote}WITH AN OPAQUE INFRARED FILTER YOU HAVE TO COMPOSE FIRST WITH THE CAMERA ON A TRIPOD AND THEN FIT THE FILTER{/pullquote}
With film you need a filter. This might be a red (Wratten 25) to remove the green and blue portions of the visible spectrum or an near-opaque filter that passes infrared only – for brevity’s sake, we’ll describe infrared filters as opaque. The red filter is a popular option because it transmits red visible light as well as infrared wavelengths, so it makes composing easy. With an opaque infrared filter you have to compose first with the camera on a tripod, and then fit the filter.
Exposure needs a bit of work but with experience this is simple enough. You soon get to know what is needed on a sunny day, when there’s most infrared around.
Focusing can be a challenge with film. Infrared radiation focuses at a different point from visible light so you may need to correct for this when using a typical lens. Infrared focuses behind the film or sensor plane when the lens is focused normally. You either have to refocus to a slightly closer distance – older lenses often have an infrared index – or stop down to f/8 or f/11 to give enough depth-of-focus to obviate the need for this adjustment. Wide apertures and telephotos do need careful handling with infrared film.
Infrared film can be home or commercially processed; if the latter, go for a specialist processor rather than a high street lab. Infrared negs needs good printing to get the most from them. Run it through a high capacity processing lab and the odds are you will end up with a set of very grey, flat-looking prints.
There are plenty of resources on the web for film infrared photography, so let’s move on to digital infrared.
Every digital sensor records infrared as well as visible light. That, of course, is a problem because the infrared contaminates the visible light, thus giving strange coloured pictures that most people don’t want. So digital cameras have an infrared blocking filter or hot mirror in front of the sensor to filter out this unwanted radiation while allowing visible light to pass through. Despite this blocking filter – although this depends on the camera – you can use an opaque infrared filter combined with a long exposure to get an infrared result. By long we are talking several seconds, so a tripod is essential even on a bright sunny day.
You’ll have to test your camera to see if it’s suitable for infrared shooting. If you are using a compact or have a DSLR with Live View, you can check this with a TV remote control. Just aim it back towards the lens – with Live View on in the case of a DSLR – and if you see the infrared emitting LED of the remote very briefly light up when you push a button, you know that your camera has some sensitivity to infrared.
There are various infrared-transmitting filters available with different cut-off points. B+W, Cokin, Hoya and Lee Filters are some of the names to look at. See the panel for more on the filters available.
Of course, an infrared filter and long exposures is fine for some subjects and if you have a solid tripod, but it’s no good for hand-held photography or moving subjects, so the other option to consider is to have a camera body converted.
If you have a DSLR redundant from a recent upgrade, that is an option to consider if you have the budget. Don’t use a DSLR that is still under guarantee because this will be invalidated.
Because a normal digital camera still has its hot mirror in place and an infrared filter cuts out most of the infrared, exposures will run to several seconds to allow enough infrared to record. Don’t use an auto mode; use manual, preferably when the sun is shining so there’s plenty of infrared around. At ISO 200, you might start at 4secs at f/8 and bracket. A quick look at the shots will tell you how close (or otherwise) you are.
Once you know what the exposure is when the sun’s out, those settings are a good starting point for similar situations.
Remember though, once a camera body is converted – the hot mirror swapped for an infrared filter – you can only shoot infrared with that body (unless you get it re-converted). You need to be really certain that this is what you want because it’s not a cheap process. More on getting a DSLR converted can be found in the above panel.
However, costs aside, there are a great many advantages to getting a body converted to infrared. There’s no need for any filtration on the lens, so you get the same bright viewing image as you do normally. Furthermore, you focus normally because the camera will be optimised for infrared wavelengths, which means you can use any lens and aperture without worrying about focus correction.
You’ll find that the camera’s exposure system also works. Just use exposure compensation or exposure lock as you would normally to fine-tune results.
If you do pay for an infrared conversion, it’s not all plain sailing. Brilliant infrared shots are yours for the taking but some fine-tuning will be needed at the capture stage as well as the post-production stage.
White-balance is something you need to look at. Shoot in AWB and the images will have a predominately red colour cast. You can correct this by taking a custom white-balance reading or by using a manual colour temperature setting. In the latter instance, go out on a sunny day with a scene comprising foliage and blue sky, then take shots at each Kelvin value until you get a look that you like.
For a custom reading, shoot an area of sunlit grass and select that image as your custom white-balance image. In the case of Nikon users you may get the ‘no good’ message so vary the exposure.
Colour infrared images out of a converted DSLR with the white-balance customised will have purple skies.
I converted my D300 with the aim of shooting infrared images akin to Kodak HIE film. This mono film gave very strong infrared, contrasty and grainy results. With a converted DSLR you can certainly get powerful infrared images with plenty of contrast, and noise – grain – is best added afterwards in Photoshop.
I set my camera up to shoot Raw and mono Fine JPEGs with white-balance set to 2630K – I couldn’t get a custom white-balance reading. The JPEGs give the required HIE-like result straight out of the camera so is a good proof of the effect.
In respect of exposure I find my converted Nikon D300’s metering system works fine. I shoot in aperture-priority AE and the results are generally good without any interference from me. However, I often bracket +/-1EV.{pullquote}A hot spot is not always obvious depending on the scene but shoot something plain like a blue sky and you will see the problem{/pullquote}
One thing you must, must test before doing any serious shooting is how the camera reacts to your lenses. Some optics can give problems, either producing a hot spot at the centre of the frame or suffering very bad lens flare – or both.
A hot spot is not always obvious depending on the scene but shoot something plain like a blue sky and you will see the problem. If your lens does hot spot it is intrinsic to the lens, and aperture or focal length choice seems to have no effect on the problem. It’s best to use another lens although there is always the Photoshop solution – the problem with this, though, is that it’s time-consuming to do it well.
The flare problem can be very annoying and one that using a lens hood probably won’t solve. The annoying thing is that the image can look fine through the viewfinder, ie there is no flare visible, but the flare appears on the final image. Wide-angles are more susceptible to the problem but telephotos suffer too when the sun is anywhere near in front of you and so use a lens hood. A possible solution is to use your hand or a piece of card to shield the front of the lens to minimise the problem.
Finally, as this issue has a strobist theme, try sticking an infrared gel filter over the flashgun’s head and you can get some very interesting images. Again, some experimentation is needed.
Get over the few technical hurdles, though, and you can have a great time with infrared photography. It might be just the thing to give your photography the creative jolt that it deserves.
Taken from the July 2011 issue of Advanced Photographer magazine