Sony has revealed that its faithful α700 mirror-based digital SLR (DLSR) is being put out to pasture and replaced with a powerful new model featuring the company's Translucent Mirror Technology. The new SLT-A77 features a 24 megapixel APS-C size sensor, an OLED electronic viewfinder that's said to provide the kind of image previewing experience previously only available with optical viewfinders and an incredibly fast full resolution continuous shooting rate. Joining the α77 is the SLT-A65 consumer-level digital camera which shares many of the newly-introduced features of the flagship model but costs $500 less (body only).

Translucent Mirror Technology features a semi-transparent mirror that stays put when the shutter release button in pressed, allowing most of the light through the mirror to the sensor but also redirects some to the AF sensor. The result is super-fast autofocus, even in video mode. Now Sony has announced the next stage in evolution of the company's TMT camera development - revealing what is claimed to be the fastest, most responsive interchangeable lens cameras in their class, and reported to outperform many professional-level DSLR cameras.

Both the new alpha cameras have been treated to a newly developed Exmor APS-C (23.5 x 15.6 mm) HD CMOS sensor with 24.3 effective megapixel resolution, which works with Sony's BIONZ image processing engine to produce ultra-low noise images. There's extended exposure-friendly ISO sensitivity, Tracking Focus keeps fast-moving subjects in sharp focus, and a new electronic front shutter curtain is said to result in a release time lag of a high-end-DSLR-matching 50 milliseconds.

Whereas last year's α55 had a somewhat tepid reception for its 1.15 million dot resolution LCD electronic viewfinder, the new kids on the block sport a brand new XGA resolution OLED Tru-Finder viewfinder - with 2,359,296 dot resolution, bright, high contrast image reproduction, five display modes, 100 percent frame coverage, and the ability to zoom into sections of an image for fine focus adjustment. It's said to be comparable to an optical viewfinder but the with ability to preview image settings such as exposure and white balance through the viewfinder, and is also capable of capturing 12 megapixel images of an enlarged central portion of the sensor, at a digital zoom factor of 1.4x or 2x magnification.

Users can also make use of the tilting 3-inch, 921,000 dot resolution Xtra Fine LCD display with TruBlack technology for previews and settings adjustment. Picture Effect in-camera creative styles seen in the NEX-C3 have also been included, along with such staples as 2D/3D Panorama and HDR.

The camera uses the AVCHD Progressive (Ver. 2.0) standard format for full high definition movie recording at a progressive frame rate of 60 frames per second. Continuous autofocus during movie recording has been further refined, and manual focusing and P/A/S/M exposure modes are also made available to video takers.

The light and durable magnesium alloy outer casing has been overhauled to provide a more comfortable grip with tactile buttons for eyes-off operation and dust- and moisture-sealed key controls that offer some protection from the elements. Each camera has a built-in flash, an HDMI port for onward connection to big screen (with Bravia Sync also included) and has Memory Stick PRO Duo / Memory Stick PRO-HG Duo; SD / SDHC / SDXC memory card compatibility. Sony says that the new models are compatible with A-mount lenses, but will also work with Minolta and Konica Minolta AF lenses.

The Sony SLT-A77 enthusiast camera is claimed to give the world's fastest continuous autofocus performance - with a burst shooting rate of 12 frames per second in Advance Priority AE mode at full resolution with full-time phase-detection autofocus. The shutter speed ranges from 1/8000 to 30 seconds, its sensitivity is specced at ISO50 to ISO16000 (which can be extended to ISO25600) and the included GPS delivers geotagging functionality.

The LCD display tilts with a little more freedom than the α65 courtesy of the world's first three-way adjustment (two-way on the α65). There are front and rear control dials and if you look down at the top of camera, you'll see a useful LCD data display. The α77 is also compatible with Sony's Memory Stick PRO-HG DUO HX series memory sticks. The reported battery life is 470 shots if using the viewfinder and 530 shots with LCD monitor.

The SLT-A77 will be available from October in kit form with a new DT 16-50mm F2.8 SSM zoom lens for US$2,000, or body-only for US$1,400.

Those with a smaller bank balance can get many of the features of the α77 at a budget-friendly price by opting for the Sony SLT-A65.

This model has a 10 frames per second burst shooting rate at full resolution, a sensitivity range of ISO100 to ISO16000, shutter speeds of 1/4000 to 30 seconds and a battery life of 510 shots with the viewfinder, and 560 with LCD display.

Also scheduled for an October release, the α65 comes as a standard 18-55mm lens kit version for US$1,000 or US$900 for just the body.

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