Sony will unveil its first, long-awaited digital single lens reflex (DSLR) camera next week, the company said Friday.The camera, which will carry the Alpha brand name, will be shown at a news conference in Tokyo on Tuesday.Single-lens reflex cameras use a mirror placed between the lens and the film or image sensor to project the image to the camera\u2019s viewfinder. The mirror moves out of the way when the picture is taken. They typically support interchangeable lenses and are preferred by professional and serious amateur photographers over the compact point-and-shoot models that dominate the digital camera market.Sony said in July last year that it had begun developing a DSLR model. Competition in the compact camera market is intense, and DSLRs typically carry higher price tags and have better profit margins. There is little compatibility between interchangeable lenses from different camera makers, so users are generally reluctant to switch brands once they have invested in several lenses.Sony will use the Alpha lens mount (called Dynax in Europe and some Asian countries, and Maxxum in North America) developed by Konica Minolta Photo Imaging. Sony began developing the camera with Konica Minolta and acquired some of the camera maker\u2019s assets this year when Konica Minolta withdrew from the camera business.About 16 million lenses have been produced for the Alpha mount, according to the two companies. A key advantage of this mount is that it relies on an auto-focus system in the camera body. This means that as auto-focus technologies improve and owners replace their cameras, the lenses can continue to be used.Sony is one of a number of digital camera makers moving into DSLRs. Earlier this year, Matsushita Electric Industrial (Panasonic) unveiled its first DSLR camera, the DMC-L1, which was developed with Olympus.-Martyn Williams, IDG News ServiceFor related news coverage, read Product Review: Sony Vaio VGN-UX50 Handheld PC.Check out our CIO News Alerts and Tech Informer pages for more updated news coverage.