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Life in widescreen - part one

Your digital camera's lens may not be wide enough to take a panoramic shot, but you can still achieve the same effect with the use of some clever image-editing software

Panoramic photos give you a much wider view of the world than you would normally capture; they can show breathtaking vistas that a single shot wouldn't be able to take in. They give you a feeling of being there that you just don't get with ordinary photographs.

However, the angle of view in a panoramic shot is far wider than the lens on a digital camera can encompass. Special film cameras have been designed to rotate during the exposure and record the picture on a cylindrical strip of film within the camera, but that's not possible with digital sensors.

There are other ways to achieve the same thing digitally, though. Digital image-editing software can 'stitch' a sequence of frames together so effectively that you simply can't see the joins.

Many perfectly ordinary compact digital cameras can take these panoramic sequences, or stitchers as they're commonly known, and it's then possible to use the stitching software that comes with the camera or a program such as Photoshop Elements to assemble them.

There are some particular requirements for images that are going to be stitched together as a panorama. The most important is that the entire sequence of shots has to be taken from the same position. The next is that they need to overlap by about a quarter or a third. This is so that the software can align each successive frame accurately and blend it with the previous one. The frames in the panorama need to match in terms of colour, exposure, focus and zoom setting, too.

But don't worry too much. Cameras that have a dedicated panoramic mode will take care of all of this automatically. You can also use cameras that have a manual exposure mode to achieve the same effect, but it's not quite as easy.

Keeping it straight

Even the cleverest camera can't remain straight for the whole sequence of shots. We've all taken shots where the horizon slopes from one side to the other and, while stitching software can accommodate small angles of tilt, it may be unable to stitch badly skewed images.

For the best panoramic results, it's best to use a tripod. This will help to keep the camera level but also, if it's the most common type with a 'pan and tilt' head, once the tripod is level, its possible to rotate the camera on the horizontal 'pan' axis to take the sequence of shots. Check the horizon is level for the first frame but sweep the camera round to check the last frame is level too.

Some tripods have spirit levels which can help to keep the whole sequence on an even keel, but setting them up can be time-consuming. It's often quicker to resort to a little trial and error and, if the overall skew isn't too bad, worry about straightening the panorama fully later on using the computer.

Common mistakes

With the camera set to its panoramic mode and securely mounted on a level tripod, there's surely nothing left to go wrong, is there? Usually, no, but there are a few problems that can upset the applecart. Rather annoyingly, cars, seagulls and other moving objects tend to keep on moving. Objects that change position within the frame between shots can cause problems for the stitching software if they're in an overlapping region.

Changing light can ruin the sequence too. If the sun's out for the start of the sequence but goes behind a cloud halfway through, there's going to be an awkward and abrupt change of tones midway through the finished panorama. If this happens there's nothing for it but to start again.

Perhaps the biggest difficulties, though, are caused by objects close to the camera. It's impossible to avoid small 'parallax shifts' between frames without expensive and cumbersome panoramic tripod heads. A lamp post, for example, might be in one position relative to the background in one frame, but in a slightly different position in the next.

The most effective way round this is to change the composition, avoiding arrangements where objects are near the camera. Alternatively, it may be possible to arrange the sequence so the object falls in the centre of one of the frames and not in an overlapping area.

It's also tempting to try to take in super-wide panoramas many frames wide, but the novelty soon wears off and this extended 'letterbox' format isn't very appealing. The ideal panoramic proportions in most cases are just a little wider than the 16:9 aspect ratio of widescreen TVs. This requires only three or four frames.

Written by Rod Lawton

This article was created: 27 November 2006.
This article was last edited: 19 March 2007.

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