Right now, in the digital camera market, the only thing that is certain is change. Trends emerging at the Photokina imaging exhibition in Germany show no end to the flurry of innovation underway in digital photography.

One of the trends is the move to pack more features into slim, pocket-size cameras. If only a couple of years ago a compact digital camera offering a resolution of 2Mp was a big thing, you can now multiply that number by 5.

Several manufacturers introduced 10Mp compact cameras at Photokina without much fanfare, including Casio, Panasonic, Olympus and Sony.

Whether consumers will find even more pixels packed into cameras is questionable. Some manufacturers appear to think 10Mp resolution is more than enough for consumers' eyes - and their wallets. "I think the pixel rush is coming to an end," said Esther Smirnovs, product manager at Panasonic's European consumer products group.

While resolution is rising, angles are widening, too. Compact digital cameras with 28mm wide-angle lens are emerging as a popular feature in many new compacts.

Panasonic introduced two new 7.2Mp compact cameras in its Lumix line, DMC-FX50 and DMC-FX07, sporting a 28mm wide angle f/2.8 lens from Leica with 3.6x optical zoom.

Canon was among the first manufacturers to offer compact cameras with a 28mm wide-angle lens, now a standard in numerous models.

In addition to high resolutions, wider angles and larger displays, manufacturers are extending zooms. If the 3x optical zoom is standard in many compacts today, Nikon has raised the bar with its 10x optical zoom CoolPix S10.

With an eye to consumer demand for small, lightweight cameras, Olympus introduced at Photokina what claims to be the world's smallest digital single lens reflex (DSLR) cameras, the E-400, which slashes a third or more of the size of standard DSLR models on the market today.

At Photokina, Panasonic, Olympus and Sigma announced an agreement to make many of their lens for DSLR cameras interchangeable based on the Four Thirds standard. The standard defines the diagonal length of the 4:3 image sensor, the image circle of the lens and the interface between the lens and camera body.

As more flat-panel TVs in the 16:9 ratio flood the market, camera makers are now offering products to meet the needs of photographers who want to shoot and view this wide-angle format. Panasonic introduced a Lumix LX2 digital camera featuring a 16:9 CCD (charge coupled device) sensor and LCD screen.

CCD sensors function, essentially, as the 'film' in digital cameras. When the surface of the CCD sensor, which is covered with pixels, is briefly exposed to light, it senses the strength of the photons as they hit different pixels. The senor records the strength in numerous electrical charges and later off-loads these charges into a processing core. The core translates the charge information into a detailed picture, defining each pixel by both light intensity and colour.