Touch-screen interfaces are often used as selling points for digital cameras. They make the rear of the camera much simpler because the designers can do away with buttons and dials, and they are both attractive and a technical novelty.

This is the display on the Sony Cyber-shot TX1. It shows some of the advantages of touch-screen technology, though also hints at some of the disadvantages too.

One of the problems is working out where to put the icons. Sony’s used a 16:9 aspect ratio LCD which means that the edges of the screen have black borders when shooting regular still photos, which are in the narrower 4:3 ratio. This means there’s somewhere to put the on-screen buttons outside the picture area, but it does mean the actual picture area is a good deal smaller than the true screen size.

Here, the camera’s in playback mode, where you can use the ‘pen’ supplied to write and draw on your saved images. Touch-screen technology is generally associated with technical novelty and fun applications rather than any serious photographic tools.

Other makers get round this by overlaying the control icons on the image itself, and this works perfectly well because we’re all used to image data superimposed on the LCD display anyway.

Even so, touch-screen controls do have a somewhat vague feel, simply because there’s no mechanical movement involved. Many makers attempt to get round this by providing audio feedback – a ‘beep’ – when an on-screen button is pressed. This does help, but touch-screen interfaces still don’t have quite the same ‘feel’ or responsiveness as ordinary controls, and can prove particularly difficult if you’re wearing gloves or have big hands.

Samsung’s used a very clever solution for its ST550 compact, however. It has a ‘haptic’ interface, which means that when you press an on-screen button the camera produces a slight vibration. This gives a pseudo-mechanical feel that’s much more effective than a simple beep.

So are touch-screen interfaces worth having? They are if they produce a camera that’s particularly slim, elegant or technically interesting, but they have no inherent advantage over conventional controls and, in fact, most of the time they struggle to achieve the same efficiency.