Price: £2,200/US$2,800/AU$2,800 (body only)
Specs: 24.3MP, Full HD video: 1080p, 102-point AF, ISO 100-25600, GPS
Different by design, the Sony Alpha a99 is the only camera in this group that doesn't feature a conventional, flip-up reflex mirror inside. Instead, it has a translucent mirror that remains fixed in place, enabling 70% of the light to pass through to the image sensor, while reflecting 30% upwards into a phase-detection autofocus sensor.
The camera's viewfinder is also fundamentally different to any of the other cameras on test. Because of the relatively small amount of light that's directed upwards from the translucent mirror, the Sony a99 relies on an EVF (electronic viewfinder).
These can be notoriously low in resolution and jerky when panning, but the unit on the a99 is a top-quality OLED display with a very high 2.36MP resolution and 100% frame coverage. It's easy on the eye, great at boosting brightness in near-dark shooting conditions and gives the advantage of showing you optional extra shooting information, such as a full-time virtual horizon or a live histogram, to help composition.
Other unusual features here are built-in sensor-shift stabilisation, a GPS for optional geo-tags and an articulated rear LCD. Sensibly, and unlike with the Canon EOS 6D, the GPS turns off automatically when you switch off the camera, extending your battery life.
Build quality is sturdy and there are plenty of direct-access buttons for clever tricks such as an autofocus range limiter (complete with a clear on-screen display).
However, overall handling isn't as slick or assured as with competing Canon and Nikon bodies. The maximum drive rate is a useful 6fps (10fps in crop mode).
Metering can be a bit on the dark side in anything other than bright sunlight, and autofocus is moveable. Even with a fast lens, the Sony a99 struggles to autofocus in low light, strangely being less competent than the APS-C based Sony a77 camera. There are 19 selectable autofocus points available, of which 11 are cross-type. However, like with the Nikon D600, they're all uncomfortably close to the centre of the frame.
Contrast can be a little lacking, and the Sony a99 typically produces darker images than competing cameras, apart from under bright sunlight.
The a99 is extremely consistent in resolution, returning the same high score from ISO 50-3200, and only really dropping off at ISO 25600.
Performance is good at lower sensitivities through to ISO 3200, but image noise ramps up noticeably from ISO 6400 onwards.
From direct sunlight to cloudy and shady conditions, colour balance from the Sony a99 is quite accurate with a hint of warmth.
Image test verdict
Images can often look a little dark and can lack contrast, but colour rendition is good and noise is low unless you use ultra-high sensitivity settings.
Read our Sony Alpha a99 review