Although they offer the ultimate in quality and flexibility, digital SLRs are simply too big for most of us to carry around all day. At the other end of the spectrum, ultra-compacts slip easily into any pocket but simply can't deliver level of image quality the serious photographer demands.

Though far from huge, the Powershot A640 from Canon is larger than many compact digital cameras on the market. It's just big enough to fit in all the features and components you'd want without compromise, and without resorting to fiddly buttons, but it's small enough to fit into a small bag or a large pocket.

Rather than using a tiny lithium-ion power pack. A hand grip to the right houses four AA-sized batteries behind a door shared with the SD card slot.

Incorporating a 10megapixel sensor and a 4x optical zoom lens with nine-point autofocus, the A640's impressive specification makes it ideal for enthusiasts, while its 21 scene modes and intelligent analysis programs ensure that novice users too can take high-quality pictures.

To the rear a 2.5in LCD panel flips and pivots to allow shooting from all manner of tricky angles. You can easily shoot over the heads of crowds or frame waist-level shots.

You get all the automatic features you'd expect, but what enthusiasts will really love are the full manual control, aperture and shutter priority modes which give you the flexibility to be as creative as you like.

This flexibility would be wasted without image quality to match, but we found shots taken with the A640 immediately invited comparison not only with the very best compact cameras but also with digital SLRs.

In a word, the quality is excellent. As we expected, there's some noise apparent above ISO 400 but in general images are extremely clean and crisp - definitely photographs as opposed to snaps.

Our one criticism of the A640 would be the lack of resolution on the LCD panel. With only 115,000 pixels, around half what we've seen on displays of a similar size, it's difficult to see just how sharp your pictures are without zooming (this is done for you automatically when manual focus is selected).

The lower resolution also makes the menus look a little less polished which is a shame, but it's actually very intuitive and easy to operate. The icon-driven menu system allows you to adjust all major settings without taking your eyes off the subject, avoiding the need to re-frame.

There's also just the right level of animation to draw your attention to what's going on without cluttering the interface. The top-mounted mode dial clicks positively into each position and individual buttons are available for exposure compensation, flash and focus modes.

Changing mode results in a large, clear icon appearing in the middle of the screen; this then flies off to the edge to take its place in the status display. You can display as much or as little information as you want, including a histogram and exposure highlight warnings.

Overall, we were very impressed with the Powershot A640. It has a rich feature set that is useful rather than gimmicky, can accept add-on conversion lenses and accessories and is useable by both novices and enthusiasts alike. Best of all, the image quality is superb.

For a lower-cost alternative, take a look at the A630 which at £269 is essentially an 8megapixel version of the same camera.

Also consider:
Fujifilm Finepix Z3
A stylish digital compact with excellent build quality

Samsung NV10 digital camera
A novel digital camera with some unusual features

Canon Ixus 900 Ti
A quality compact digicam from Canon, but one that fails to raise the bar