The E system from Olympus is the only digital SLR system designed from the ground up to be wholly digital. All of the other D-SLR systems from other manufacturers are based, at least in part, on existing 35mm film SLR standards, including body designs, lens mounts and even lenses.
There are advantages to both approaches. For the other manufacturers, it means that existing SLR system users can make the switch to digital without having to replace their expensive lens collections, and will be familiar with the controls and handling of their new camera. Brand loyalty is a major feature of the SLR market, and a Canon, Pentax or Nikon user is likely to stay with the same brand for life, spending thousands of pounds on accessories - a highly profitable market of which all the manufacturers would like a part.
Olympus however took the brave decision in 2001 to cease production of its long running and extremely popular OM 35mm SLR system, and instead to develop an all-new digital SLR system based on the high-quality 18 x 13.5mm 4/3 (“Four Thirds”) format Full Frame Transfer sensor, with a new smaller, lighter lens format purpose-built to match. A few other manufacturers have also signed up to develop 4/3 format cameras and lenses, but so far Olympus is the only one to have launched actual products, starting with the E-1 professional SLR in 2003, which was well received but priced too high to compete with the consumer-oriented digital SLRs that are now starting to dominate the market.
The launch in 2004 of the second 4/3 SLR, the E-300, was less popular, which is odd because the compact 8MP SLR was a very good and competitively priced camera. However it had a body shape resembling a high-end compact camera, which may have put some people off.
Finally Olympus has come up with a product that can take on the likes of the Canon EOS 350D, Nikon D50 and Pentax *ist DL. The E-500, launched at the end of last year, is a conventionally-styled lightweight and relatively compact D-SLR which offers all the advantages of the 4/3 system at a price of just £549 including a 14-45mm standard zoom lens. With 8MP performance and a wide range of manual and creative options available, it is aimed squarely at the amateur/hobbyist end of the market.