Sony is set to introduce shooting speeds of up to 10fps, as well as video, in its latest Alpha DSLR cameras, the Alpha 55 and Alpha 33, by using a new non-moving ?translucent? mirror. Echoing the technology of the pellicle mirror in Canon?s EOS RT of 1989, Sony?s new semi-transparent mirror allows light to be fed simultaneously to a camera?s imaging sensor and AF system, removing the need for a moving mirror and providing the potential for much improved focus tracking as well as active AF in Live View and video modes.

The Sony Alpha 33 and Alpha 55 will be the first Sony DSLR cameras to offer a video capture facility. By using what Sony calls ?Translucent Mirror Technology?, phase detection autofocus during video recording becomes possible for the first time in a DSLR camera. The company says this new technology will significantly out-perform the contrast detection AF systems currently used by other manufacturers for focusing during video capture.  

Eliminating the requirement for mirror movement between frames has enabled Sony engineers to achieve high frame rates in these two new cameras: the Alpha 55 will be capable of 10fps in Continuous Priority mode with tracking AF, and the Alpha 33 up to 7fps in the same mode.

In another unusual move Sony has equipped its new DSLR models with electronic viewfinders instead of optical finders. The 1.15 million-dot ?Tru-Finders? will provide 100% image coverage, a digital level gauge and grid line display options.

The 3D Sweep Panorama mode that was first seen in the DSC-WX5 and the company?s NEX micro system cameras is also to be incorporated into the new Alpha bodies, as will SteadyShot, an anti-dust system and auto-HDR modes.

Of the two cameras the Alpha 55 is the higher specified, featuring a Sony Exmor HD APS-C size 16.2 million-pixel CMOS sensor, whilst the Alpha 33 has a 14.2 million-pixel CMOS sensor. Each camera will have a sensitivity range of ISO 100-12,800, which can be extended to ISO 25,600 by using multi-frame noise reduction mode.

The tilting screens of previous Sony Alpha cameras have also been upgraded and the 3in 921,000-dot screens now have both a tilt and swivel action.

The two new models will be available in the UK from September. Sony has yet to confirm pricing.

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