by Cynthia Anderson

Billed by Sony as “the most innovative interchangeable lens digital cameras” that the company has ever created, the SLT-A55 and SLT-A33 were introduced this fall. (“SLT” stands for “Single Lens Translucent.”) The main feature that sets these Alpha-series cameras apart is Sony’s new Translucent Mirror Technology™, in which a fixed-position, translucent mirror allows light to be received by both the image and autofocus sensors. In other words, these cameras can autofocus and shoot simultaneously and continuously.

Mark Weir, senior technology manager for Sony Digital Imaging, says, “What we’ve done is change the decades-old basic structure of the moving mirror. The fixed translucent mirror allows the camera to shoot faster while focusing more effectively than any previous DSLR.”

With the new technology, these cameras can focus quickly at high speeds — up to 10 fps for the A55 and up to seven for the A33. As of August 2010, these were the fastest speeds in the industry for an interchangeable lens camera under $4,000. A new 15-point autofocus system and continuous Phase Detect AF assist in tracking rapidly moving subjects. Weir adds, “These cameras offer outstanding image quality, plus multi-shot compositing for extraordinary available light photography and even continuous autofocus during Full HD movie capture.”

Because the cameras don’t have a moving mirror mechanism, the body size is significantly more compact than traditional DSLRs. “The compact size helps create an ‘always with you’ event coverage camera that can excel in many areas,” says Weir. “The extraordinary shooting speed makes the A55 and A33 great sports and wildlife cameras; Auto HDR and 3D Sweep Panorama are great benefits for nature and landscape photography; and the Full HD video with a large image sensor and interchangeable lenses makes them great video cameras.”

Both cameras offer a fully articulated, three-inch LCD screen that hinges along its lower edge and can be reversed for protection when the camera is not in use. Weir observes, “An articulated LCD can change your point of view by allowing you to shoot from angles otherwise difficult or impossible to reach.” The Tru- Finder™ electronic viewfinder provides 100 percent coverage, and full-time Live View is available using either the viewfinder or the LCD.

Advanced Shooting Features
Special shooting features of the A55 and A33 include:

  • Auto HDR: shoots and combines three frames into a single high dynamic range (HDR) image
  • Multi-frame NR: shoots and combines six frames into a single image for smooth, low-light imaging with half the noise level
  • Hand-held Twilight: shoots and combines six frames into a single image for blur-free night photography without a tripod or flash
  • 3D Sweep Panorama™: creates two images from a single frame so that panoramic photos can be viewed in 3D on compatible devices
  • Auto+: produces cleaner, more dynamic pictures by combining up to six shots to optimize dynamic range

Video Capture
Whereas most DSLRs with video capability visibly “hunt” for focus, resulting in delayed response and blurry videos, the A55 and A33 use continuous Phase Detect AF during video shooting. “These are the first cameras in the world to maintain continuous phase detection autofocus while recording Full HD AVCHD video,” says Weir. “Even fast action and subjects that move quickly towards or away from the camera are easy to keep in focus.”

The APS-C sensor is nearly 20 times larger than that of a traditional camcorder image sensor, providing more creative control and professional-looking results. The large sensor can also capture dramatic background defocusing effects that are beyond the range of conventional camcorders.

In AVCHD mode, the cameras can record videos up to 29 minutes long at 1080i (50/60 fps), which offers excellent quality for viewing on an HD TV. In MP4 mode, the cameras can record 1080p at 30fps.

A55 and A33 Comparison
As mentioned previously, one of the key differences between the A55 and the A33 is the maximum shooting speed: 10 fps for the A55 and 7 fps for the A33. Another is the megapixel count: 16.2 for the A55 and 14.2 for the A33. (Both cameras use Exmor APS HD CMOS sensors.)

As an extra perk, the A55 has built-in GPS capability, recording orientation and elevation data as well as date and time. The A55 is slightly heavier (441g versus 433g for the A33) and also offers faster rates for buffer in continuous shooting: for example, 35 frames for JPEG Fine in the A55 and 16 frames in the A33.

Both cameras are fully compatible with all Sony A-mount lenses, including the recently released Carl Zeiss® Distagon T* 24mm F2 ZA SSM, DT 35mm F1.8 SAM and 85mm F2.8 SAM. In addition, both cameras come supplied with the following software: Picture Motion Browser 5.3 (image cataloging and browsing, Windows), Image Data Lightbox SR 2.2 (image browsing and workflow, Windows/Mac) and Image Data Converter SR 3.2 (RAW converter, Windows/Mac).

Pricing and More Information
Pricing for the A55 is approximately $750 for body only and $850 with an 18- 55mm zoom lens; the A33 is approximately $650 for body only and $750 with the zoom lens. For more information, visit www.Sonystyle.com/retail.

Weir sums up, “An emerging pro would consider buying these cameras for their unique responsiveness, low-light sensitivity, Full HD video and image quality, combined in a remarkably portable package, ideal for use in the field. They offer responsiveness and versatility that very few DSLRs can match.”

Cynthia Anderson is a writer and editor based in the high desert of Southern California.