SOMEONE SAYS INFRARED

 visible light

 F SOMEONE SAYS  INFRARED  to you. what comes to mind? The remote control for your TV? Goggles that can see in the dark? Invisible beams that trigger alarms? Actually, all three would be correct because infrared has many applications-although the use that should appeal to you most is in creative photography.

Infrared is a type of light found outside the visible spectrum, so the human eye can t detect it-which is why you can turn your TV on using an infrared remote control, but not actually see anything. The remote is sending out a beam of light, but it s invisible to you. Nothing can be done to human vision to change this. However, digital cameras can be adapted to record the effects of infrared radiation, ard the resulting images are like something from another world: blue sky and water go black; people take on a ghostly pallor that looks spooky ard unnerving; leaves, grass, plants and crops come out white; and images have a subtle diffused glow about them that adds an overall dreamy effect.

American physicist and inventor Robert Williams Wood is thought to be the first person tc have created photographic images using infrared light, back in 1910. Later, infrared-sensitive film was used during World War II in aerial surveillance to locate enemy positions. For the last few decades, however, it has also been used by photographers to create fantastic images, traditionally using specialist infrared-sensitive films, but in recent years, digital cameras have become far more popular. In this month s The Complete Picture, we tell you everything you need to know to start shooting in infrared.

Seeing red

While the human eye can only  see  a limited part of the electromagnetic spectrum (a fancy term for light), the sensor in your digital camera is sensitive to a much wider range of that spectrum; from ultraviolet at one end to near-infrared at the other. During manufacture, however, the vast majority of digital cameras are fitted with an infrared blocking or cut  filter. In order to record infrared light with your DSLR, you therefore need to find a way around this.

The easiest and cheapest way is to put an infrared-transmitting filter on the lens, which blocks out most of the light in the visible spectrum so that the image is captured using near-infrared light. Suitable filters include the Hoya R72 and the B+W 092 or 093. Not all DSLRs will record infrared using a filter, but you can find out if yours will simply by pointing a TV or audio remote control towards it and pressing any button on the remote. If you can see the infrared beam being emitted by the remote, or any trace of it recorded on the picture you take, then the camera is capable of recording I infrared light and will produce good results with an IR filter on the lens.

The main problem with using an infrared-transmitting filter is that you can t see or focus through it because it blocks out visible light, so you have to compose the shot and manually focus your lens before attaching the filter. Infrared filters also need long exposures-often several seconds-which means you must mount your camera on a tripod to avoid shake and the subject needs to be static, otherwise it will blur.

The expensive but infinitely more practical option is to have a digital SLR (or compact) modified internally to record infrared light. This involves removing the IR blocking filter from the sensor and replacing it with a filter that blocks out most of the visible light, but transmits light at the red and near-infrared end of the spectrum.

 

An immediate benefit of using an infrared-modified camera is that you don t need to use filters on the lens to admit infrared light, which means exposure times are hardly any different from those required by an unmodified camera. In fact, an infrared camera operates just like a normal digital camera-you can shoot handheld, van/ the ISO in different lighting conditions, change lenses and so on. The only difference is the look of the images produced-out of this world!

Infrared technique

As infrared lens filters and infrared sensor filters block cut most of the visible light and admit mainly infrared light, don t be surprised if your camera s metering system struggles. Underexposure is likely, but you can correct that using exposure »

compensation. What you ll probably find is that a similar amount of exposure compensation is required all the time with your camera, so you can leave it dialled in and use that as your starting point.

 visible light

In both cases, as well as checking the preview image, get into the habit of checking the histogram. Older DSLRs have small preview screens compared to the latest models, so they re not as easy to use. Also, infrared images tenc to contain a lot of light tones, so you want to ensure they re well exposed, but not to the point that the highlights start to blow out. The histogram will tell you that more clearly than the preview image.

In order to achieve optimum image quality, it s also a good idea to shoot in Raw rather than JPEG, so your infrared images are uncompressed. You need to retain as much

information as possible in those files, so you ve got more latitude when editing them. It is possible to produce superb images by shooting in JPEG, but Raw is always superior.

Levels of infrared radiation vary depending on the weather conditions. Bright, sunny days are the most effective for infrared photography because blue sky goes very dark and white clouds really stand out. Foliage and plant life also reflect a lot of IR radiation in sunny weather, so it comes out crisp-white and contrasts brilliantly with the dark sky. You can take great infrared shots in the middle of the day, when the sun is high, the light harsh and shadows dense. This is normally considered a bad time to shoot conventional landscapes as the light quality isn t particularly high, but for infrared it s ideal, so you can shoot non-stop

throughout the day, even in the middle of summer.

In terms of subject matter, landscapes and woodland are an obvious choice because they show infrared effects so well, especially during spring and summer when foliage is lush and abundant. Old buildings, such as castles, churches, cathedrals and stately homes are also perfect for the infrared treatment-particularly if they re surrounded by trees or have creepers growing on their exterior. The late Sir Simon Marsden made a career out of shooting infrared images of haunted sites and ancient architecture-you could quite easily scare yourself just looking at his photographs!

As infrared images tend to have quite a stark, graphic look to them, you can use an infrared camera to capture mocern architecture and bold abstracts. Infrared is also well suited to portraiture, both in the studio and in natural light. Pale skin tones and dark eye sockets could never be described as flattering, but on people with the right kind of  look  the effect can work brilliantly and is well worth a try. Alternatively, use infrared to produce humorous portraits of your kids-move in real close with a wide-angle zoom and get them to pull faces.

Lenses for infrared

Talking of which, yoLfind wide-angle lenses far more useful than telephotos for infrared photography-the stretched perspective, exaggerated scale and monstrous field-of-view suits the medium and allows you to produce compositions with a real  wow  factor. Wide lenses also allow for lots of depth-of-field so

you can achieve front-to-back sharpness. For DSLRs with APS-C sensors, a zoom in the 10-20mm/ 12-24mm range will be ideal.

Infrared light focuses on a slightly different point from visible light. Traditional manual focus lenses used to have an infrared focusing index marked on the barrel so that if you were shooting infrared film, you could focus the lens normally, then adjust it so the infrared index was used instead, to ensure the subject was sharp. This isn t necessary with a modified infrared camera because the focusing is recalibrated during conversion, so you just focus as normal. Providing you shoot at f/8 or smaller, depth-of-field will be so great that any focus shift will be compensated for anyway.

That said, some lenses perform better than others when used on a

digital infrared camera, so if you send a camera in for conversion, it s worth mentioning which zoom you re likely to use on it most of the time. This way the technician can bear it in mind when recalibrating the camera and maybe offer you some tips for using it. Some wide-angle zooms produce quite soft results when used on an infrared camera-unless you stop the lens right down to f/16 or f/22, for example-while others suffer from a flare spot in the centre of the frame.

If you hit the odd obstacle like this, itwell worth making the effort to overcome it. Digital infrared photography is far easier and more versatile than working with infrared film ever was, but the results can be truly stunning. And, anyway, what else are you going to do with that old DSLR of yours, other than use it as an expensive paperweight!

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