At a press conference on August 24 in Henry's flagship store in downtown Toronto, Sony of Canada Ltd. announced a pair of new Alpha-series interchangeable-lens cameras that employ new Translucent Mirror Technology. Their new viewfinder and focusing technology allows very fast burst rates in still photography, and very responsive autofocus in both still and video modes.

Like Sony's Alpha-series DSLRs, the new a33 and a55 employ APS-C sized image-sensors and accept Sony a-mount lenses. The new cameras look much like a DSLR, complete with a viewfinder hump on the top centre, but are somewhat smaller. However, these are not DSLRs, because they do not have a reflex viewfinder.

Like a DSLR, they have a mirror in front of the sensor; but the mirror is translucent, and stays fixed in place during composing and shooting. Most of the light coming through the lens passes through the mirror to the camera's Exmor HD CMOS image sensor. But a small amount of light is directed to a newly developed 15-point autofocus module in the viewfinder hump.

All DSLRs use phase-detect AF in still shooting when the reflex viewfinder is employed, but almost all models shift to a contrast-detect AF for Live View. Some DSLRs that can shoot video rely on contrast-detect AF in video mode; and in many cases, AF does not function in video mode.

On the a33 and a55, the translucent mirror does not have to swing up and out of the way for a picture to be taken, allowing full-time phase-detect autofocus, which is much more responsive than typical contrast-detect AF, especially in low light. In the words of David Oyagi (in photo at top of story), Product Manager at Sony of Canada, the new cameras can "focus between the moments."

Like the mirrorless interchangeable-lens cameras that have been hitting the market over the past couple of years (Panasonic's and Olympus' Micro Four Thirds models and Samsung's NEX-10, as well as Sony's NEX-3 and NEX-5), the a33 and a55 use full-time Live View. Photographers can compose images on three-inch 921,600-dot high-contrast LCD on the rear, or a 1.15-million-dot eye-level electronic viewfinder. Both the Tru-Finder and TruBlack LCD are very sharp, and provide 100% frame coverage. The rear LCD on both cameras is fully articulating, allowing low-level and overhead shooting in both landscape (horizontal) and portrait (vertical) layouts. The eye-level viewfinder offers several viewing options, including spirit level, focus magnification, and rule-of-thirds grid lines.

The new cameras have extraordinarily fast still shooting capability, with continuous AF: seven frames per second on the a33 and 10fps on the a55. Because of the Translucent Mirror technology, full-time focus and fast burst shooting is available with both the eye-level viewfinder and rear LCD.

The new cameras feature full HD video capability in AVCHD or MP4 formats, with full-time phase-detect AF and manual-focus capability. The cameras' large sensor allows photographers to obtain a much narrower depth-of-field, when they select a wide aperture. This will isolate a subject against a blurred background, for more movie-like results. Alternatively, photographers can choose a narrow aperture to keep the whole scene in focus and to achieve a slower shutter speed in bright settings, for a less jerky effect, but will have to focus manually.

The a33 and a55 both feature Sweep Panorama, for automatically creating panoramic images by panning the camera and holding the shutter button. A newer feature is 3D Sweep Panorama, whereby the camera captures left- and right-eye images while the user pans the camera; these can be viewed as 3D images through Sony Bravia LCD 3D TVs and matching 3D glasses. Other features include multi-shot noise-reduction, whereby the camera captures up to six shots and then blends them to reduce noise; Twilight mode, whereby the camera takes six short exposures in low-light situations and then combines them, to prevent image blur, and Auto HDR, for blending three exposures of a high-contrast scene into an image with detail in both highlights and shadlows.

Both cameras will be available in September in a kit that includes an 18-55mm f/3.5-5.6 standard-zoom lens. The a33 has a 14.2-megapixel sensor and will retail for $800 in Canada. The a55 has a 16.2MP sensor, and also adds GPS for geo-tagging photos. It will retail for $900.

Article Tags:  sony, alpha, a33, a55, translucent mirror, sweep panorama, exmor, trublack, tru-finder, phase-detect