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A Guide to Infra-red Photography |
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This is the means of photographing an image not as you and I would see it, with visible light but using invisible Infra-Red. Infra-red is essentially heat and any object (including people) warmer than its surroundings will give off heat in the form of infra-red. As a result, this method can produce startling, surreal and sometimes ghostly images of a world you and I would otherwise never see. |
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This all begs the questions how on earth do you photograph something you cannot see? With film cameras this requires the use of specialised infra-red film but here I will discuss the method for digital cameras, which is the same but without the need for specialised film. |
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It should be noted that cameras (film or digital) are generally not built to be sensitive to infra-red as this could effect the quality of the 'visible light' image. With digital cameras this tends to be a side-effect of how some sensors (CCDs) work. |
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Firstly you need to ascertain if your camera is infra-red sensitive and fortunately most of us already have the tools to do this. Point an IR remote control (for your TV or video etc) at your camera, press a button and take a photograph. An exposure of half a second or more may be required as the remote control signal is not continuous but flashes and a shorter exposure may miss this. Alternatively if your camera has a 'live view' facility via its LCD screen you will see the effect without having to take a picture. |
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The infra-red signal from a TV remote control 'seen' by my camera. |
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The next issue is how to filter out all of the visible light to give just an infra-red image? This is done with an infra-red filter which does just that. These can be bought brand new from as little as £30 and can be either threaded (see image right) or square for use in proprietry filter holder systems such as Cokin. When you look at these filters they will appear jet-black because they are doing what they should....block out all visible light. |
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A screw mount Infra-red filter. Attaches to the front of your lens. |
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Taking a Picture |
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Since the filter blocks out all visible light all through-the-lens metering including auto focus is rendered useless! To this end everything must be done manually |
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Firstly, the image needs to be framed and focused manually with the filter removed (otherwise you won't see anything!). Carefully place the IR filter on the lens taking care not to disturb anything. The actual exposure of the image will have to be trial and error but as a starting point use f-5 at 4 seconds. To adjust the exposure I would recommend adjusting the time not the aperture. Obviously for these exposures a tripod and cable release (or the camera's built in timer ) are essential. |
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Until you've taken the picture you're never quite sure how it will look so experiment. Foliage produces the best results but not all plants react in the same way. |
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Before and after images. Visible light on the left and infra-red on the right. |
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