Sony’s recent A33 and A55 cameras are packed with innovative features, not least of which being their translucent mirrors and electronic viewfinders. As such, they’re not technically SLR cameras, even though they’re designed to compete in that arena.
The A580 reviewed here bears many similarities with both, but it’s a true SLR with a flip-up mirror and optical viewfinder. Considering that we found the A55’s translucent mirror technology to be somewhat flawed, the prospect of Sony’s other recent innovations in a more conventional package shows a lot of promise.
The A580 is a much bulkier camera, weighing in at 809g with its 18-55mm kit lens. Its detailed 3in screen articulates up and down, although it doesn’t flip right around for self-portraits. There’s a reasonable number of single-function buttons covering ISO speed, drive mode, dynamic-range processing and exposure compensation and lock. The navigation pad is dedicated to controlling the autofocus point when not browsing menus.
A big problem for most SLRs is that live view disables their phase-detect autofocus systems. Instead, autofocus is via the contrast-detect technique used by compact cameras, but this is often extremely slow and cumbersome on an SLR. Sony’s solution in the A580 isn’t as groundbreaking as in the A55, but it’s just as effective. There are two imaging sensors – one for capturing 16-megapixel photos and another just for live view. The latter’s position inside the camera means it doesn’t interfere with the 15-point phase-detect autofocus system, which continued to work just as effectively as when using the optical viewfinder. The live view sensor is more cropped than the captured image and looks noisy in low light, but these are limitations we’d happily live with. It’s also possible to switch to live view from the main sensor and apply a digital magnify function when fine-tuning manual focus.
We’ve seen the same technique used in the A550 , but this time around there’s a snag. The A580 is the first Sony DSLR to record video, but to do so it must switch to its main imaging sensor. That means – unlike on the A55 – there’s no autofocus while recording. We’ll not hold it against Sony that it doesn’t attempt contrast-detect autofocus while recording, as rival cameras from Canon and Nikon make such a hash of it that it’s not worth using.
