Review units for Sony's long-anticipated replacement for the Alpha A700, the Sony Alpha A77, have finally made it to UK shores, although the worst flood disaster to strike Thailand for 50 years has hampered the camera's official release into the market. UK photographers may need to bide their time before they can own one of these formidable new cameras, but in the meantime, we're pleased to be able to deliver our verdict on Sony's latest innovation.

It's been four years since Sony turned its attention to the semi-pro sector of the camera market, but the unique technology and burgeoning feature-set that its latest creation boasts is testament to the hard work that's been going on during that time.

Sony introduced its Alpha A700 in 2007: the company's first foray into the semi-pro DSLR category. While the A700 attracted its fair share of followers, it failed to make much of an impact on the market shares of 'big guns' Nikon and Canon.

Sony alpha a77 review

In response, it seems that Sony has decided to try a different tack: in an ambitious move, the manufacturer is now attempting to take on the powerful prosumer DSLRs that currently set the benchmark for semi-pro cameras, bringing its revolutionary TMT (Translucent Mirror Technology) to the advanced photographer.

Features

Scanning the new Sony Alpha A77's specifications, it's impossible to be unimpressed with what's on offer. The camera is positively overflowing with up-to-the-minute technology that either matches or supersedes the competition.

Boasting a new 24.3MP APS-C format CMOS sensor, 19-point autofocus (AF) system, 12fps continuous shooting, Full HD (1080p) movie recording and the highest resolution electronic viewfinder we've seen to date - to name a select few - it's clear that Sony isn't taking any prisoners in its battle against the traditional DSLR.

Sony alpha a77 review

While it may look similar to its rivals on the outside, internally the Sony Alpha A77 is an entirely different beast. Building on the SLT (Single Lens Translucent) technology that Sony brought to the digital camera market last year, the manufacturer is looking to capitalise on the main benefits that this design affords - namely fast full-time AF and continuous shooting.

For the uninitiated, the Sony Alpha A77's mirror is semi-translucent and splits the light entering through the lens between the imaging sensor and separate phase detection AF sensor. This means that - unlike the mechanism inside a DSLR - the mirror doesn't have to swing out of the way in order for a shot to be recorded, resulting in new breakthroughs in terms of operational speed and performance.

Although the technology itself isn't new (Canon first featured a Pellicle mirror in its analogue Pellix in 1965) Sony's implementation of it in a semi-pro digital camera is, so it should be applauded for what it's achieved.

Sony alpha a77 review

As we've already mentioned, due to the nature of the SLT design, the Sony Alpha A77 features an electronic viewfinder (EVF) in place of the traditional optical version you find on a DSLR. One of the main disadvantages of the SLT system is that less light makes it onto the sensor, resulting in a dimmer view of the scene through the lens (as well as potentially hampering low-light shooting performance).

EVFs have been met with their fair share of criticism over the years, but recent developments mean we've started to see fairly significant improvements in their level of sharpness and clarity. We're pleased to report that the Sony Alpha A77's offering is leaps and bounds ahead of anything we've experienced before, with a very impressive 1.3cm, 2,359,296-dot resolution OLED screen that provides the closest performance to an optical viewfinder that we've had the pleasure of using to date.

In addition to the headline features we've already mentioned, the Sony Alpha A77 provides automatic and scene, as well as a whole raft of manual exposure modes, Sony's superb Sweep Panorama mode and 3D shooting capability.

Built-in GPS, a three-inch, high resolution, 921,000-dot three-way tilting LCD and SteadyShot INSIDE image stabilisation bolster this highly-specified camera's feature set even further. Add an extensive range of customisable features available via the menu system, and the Sony Alpha A77 certainly looks like it's well-equipped to take on its DSLR rivals.