Features

There are a number of useful things you can do with a digital camera that you can't do with most film cameras. Most compact digital cameras that use their main colour screens for composition can also overlay a variety of graphics to improve your shots. Many offer a 3x3 grid, which can help with alignment or avoiding squint horizon lines - that is, where the horizon line isn't at right angles to the edge of the frame. If your camera offers this facility, you can normally switch the grid on and off by pressing the Display button.

These grids also help you apply the established photographic rule of thirds, where placing key objects (such as a person's face) at the points where the lines intersect will deliver a more pleasing composition.

When it comes to judging an exposure, you can just check the screen. But there is a more scientific way. Many cameras have a histogram facility that's available on playback. This displays a graph revealing the range of tones in an image from black on the left to white on the right. If the graph is biased towards or stops dead at the left or right side, it indicates an under- or overexposure. More sophisticated cameras may offer a live histogram facility that shows a constantly updated graph of tones as you compose your shot. This shows you the technical effect of an exposure adjustment before taking the picture.

On the subject of checking photos, always zoom in on important images after taking them to check that they're truly in focus. Digital camera screens may be great, but they're not sufficiently detailed to reveal any problems unless you zoom in for a closer look.

Modern cameras now allow you to apply various digital effects, such as black and white or sepia filters, while others may let you crop an image or even retouch red eye. While software on a PC ultimately offers greater flexibility, it can be handy to use these in-camera editing facilities if you're connecting directly to a printer.

One of the biggest perceived benefits of digital over film is being able to insert a huge memory card and have enough space for hundreds or even thousands of photos. In an ideal world this would be a great advantage, but always bear in mind the possibility of losing your camera or having it stolen. You stand to lose a lot of images, so you might prefer to use a number of smaller cards rather than a single huge one.

If you're on holiday in an area where theft is common, you could visit an internet café with CD-burning facilities and post a disc of images to yourself at home. Alternatively, if the café has a fast and unlimited internet connection, you could upload images to a personal website for safe storage or email them to yourself.

	1 Many cameras can overlay a grid to help with composition.

	2 Histogram graphs reveal the range of tones in an image.

	3 In-camera effects can turn photos black and white if desired.