Sony has announced the launch of the three new digital SLRs into its "Alpha" range, the 24.6-megapixel a850 and the a500 and a550.

The a850, comparable to the previous flagship model the a900, gets a full-frame, 24.6 effective megapixel Exmor CMOS sensor and dual BIONZ processors.

That full-frame capture is backed up by an optical glass pentaprism viewfinder with 98% coverage as well as a "photo quality" 2-inch "Xtra Fine" LCD.

The camera boasts "SteadyShot INSIDE" for four-step anti-shake performance and what's said to be a fast, high-accuracy 9-point AF with 10 focus assist points.

Sony describes the camera's build as rugged, stating that the a850 "is ruggedly built for dependable performance in gruelling conditions with a high-tensile aluminium chassis and all-magnesium alloy body shell" and has rubber seals on all the camera's exposed bits.

Boasting rechargable battery life good for 880 shots, the DSLR takes Sony's Memory Sticks up to 32GB and comes complete with an adapter.

The a850 will be available from September 2009, with a new 28-75mm lens due to go on sale from November 2009.

The new Alpha 500 and 550 models are said to be easy to use and offer effective megapixel resolutions of 12.3 and 14.2 respectively.

Offering Sony's new enhanced BIONZ processor, the cameras are capable of high-speed continuous shooting up to 5fps with the optical viewfinder with the a550 capable of 7fps in "Speed Priority" mode.

Sony says that enhanced quick AF "Live View" captures fast-moving action and the DSLPs get "SteadyShot INSIDE", face detection tech and smile shutter too as well as a manual focus check in Live View mode.

The a500 has a 3-inch "Clear Photo LCD Plus" screen while the a550 gets a 921k dot, 3-inch "Xtra Fine" LCD screen that tilts 180-degrees.

Another feature highlight worthy of mention is the new Auto High Dynamic Range mode that claims to capture a huge range of shadow and highlight detail by combining two frames shot at different exposures for an improved image.

Battery life boasts come in at 1000 shots for the a500 and 950 for the a550 while the new VG-B50AM Vertical Control Grip accessory holds up to two extra batteries.

The a550 and a500 digital SLR cameras are due to be available from the end of October 2009.