After buying Minolta in 2006, Sony has only outed one camera with a 24 x 36 mm sensor—the Alpha 900 (plus a scaled-down version, the Alpha 850). So while Sony has since released twenty-one SLRs with APS sensors (15 x 23 mm) there has been no real replacement for the Alpha 900, despite the fierce competition between the Canon EOS 5D Mk II and Nikon D800.
But any impatient owners of full frame Sony and Minolta lenses can now breathe a sigh of relief, as the Alpha 99 is here. Sony is back in the game with a 24 x 36 mm sensor and a new alternative to the EOS 5D Mk III and D800.
But guess what? The sensor maintains the same 24-Megapixel resolution, far from the 36 Megapixels of Nikon's D800. As a result the pixel density remains under 3 Mpx/cm², which should make for excellent sensitivity (the sensor is considerably less dense than the excellent 16-Megapixel APS sensor used in the likes of the D7000 and K-5, for example). Although it's no match for the Nikon D4 or Canon 1D Mk IV (around 2 Mpx/cm²), that's still pretty good.
Another interesting thing about this sensor is that it has built-in phase-detection sensors like the sensors seen in Sony's recently announced NEX-5R and NEX-6. These assist the standard 19-point SLR autofocus system. The standard AF system should handle big differences in focus more effectively, while those on the sensor are more about fine-tuning. However, the autofocus system's coverage is a little on the tight side, as the AF points are all quite central, especially around the sides of the frame (they don't even reach the rule-of-thirds lines). On this front, Canon and Nikon are still one step ahead.
Another field in which Sony hasn't matched its rivals is the viewfinder. The Alpha 99 has exactly the same viewfinder as the Alpha 77. This is comparable in size to the viewfinders in the EOS 5D and D800, which is a real advantage in the Alpha 77 compared with most other APS SLRs. But for a full-frame model the stakes clearly aren't the same, with the lower sharpness and detail and the unnatural image likely to stand out above anything else.
Finally, Sony still hasn't built a flash into its full-frame SLR. And there's really no possible justification for that—the Alpha 77 (with the same viewfinder) has a flash, and Nikon has managed to make a model with a 24 x 36 mm viewfinder, a flash and a weatherproof body.
Some Advantages
That said, the Alpha 99 is a camera that has plenty going for it. First of all, the body is derived from the Alpha 77, which makes this the lightest and most compact full frame SLR on the market right now, and it keeps the same advanced weatherproofing too. The A99 is also the only 24 x 36 mm SLR with a mechanical stabilisation system, which is sure to be handy for anyone using old or wide-angle lenses.
Another great feature inherited from the Alpha 77 is the swivel screen, which can be a real selling point for anyone looking to shoot video on a tripod. Plus, while competitor models slow down considerably when you switch away from the SLR viewfinder system, there's no difference in this camera between using the screen or viewfinder.
The electronic first-curtain shutter also makes this camera quieter than its competitors, and the silent settings wheel (as seen in camcorders) means you can change settings easily while filming.
Sony has paid particular attention to the video mode in the Alpha 99, which records Full HD footage at 24, 25, 50 and 60 fps. It has a built-in stereo microphone with a full range of audio options. In addition to the microphone port, the Alpha 99 has a headphone out so you can check the sound as you go. A portable audio mixer with two XLR inputs is sold separately. To attach this to the camera, Sony has finally abandoned the mount it inherited from Minolta in favour of a proper ISO accessories hot-shoe. It can therefore be loaded with accessories designed for camcorders (anyone with a previous-gen Sony flash can pick up an adapter).
One last thing—the Alpha 99 has two SD memory card slots, so unlike D800 and EOS 5D Mk III users you won't have to juggle two memory card formats.
The Alpha 99 isn't likely to be cheap, that's for sure. At this end of the market, the video mode (especially the autofocus) is likely to be the A99's main stand-out feature. So the image quality will need to be pretty much perfect if it's going to outweigh some of the more unusual aspects, like the electronic viewfinder and the fact that there's no flash.
