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(Pocket-lint) - Sony’s SLT-A77 has to be one of the most hotly-anticipated cameras of recent years. Since the Alpha A700 was pulled from production there’s been something of a gap in the Alpha lineup – a gap that the A77 looks to fill. But with its SLT (Single Lens Translucent) construction, it’s not a straight DSLR replacement. So, is this forward-thinking, DSLR-beating material at its best?

Single Lens Translucent ?

Ah, acronyms. In the past few years digital camera technologies have evolved in leaps and bounds – the staple DSLR has seen mirrorless CSC (Compact System Camera) rivals and now the latest Single Lens Translucent (SLT) tech adds to the pile.

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For the most part an SLT is similar to a DSLR, but it has a translucent mirror that means light can always pass through to the sensor without the mirror needing to move out of the way to make an exposure. Light is still reflected from the mirror to an autofocus sensor, but there’s not enough light left to successfully engineer an optical viewfinder, so the SLT uses the readout from the sensor to feed an electronic viewfinder (EVF) instead. The much-maligned EVF won’t be to all tastes, but it’s part of the payoff because, on the up side, those permanent light streams mean continuous autofocus can take place even while capturing a shot and, thanks to no mechanical mirror movement, faster burst speeds than DSLR cameras.

In the case of the SLT-A77 we’re talking super speeds of up to 12fps with continuous autofocus at its full 23.4MP resolution. To put that in perspective: even Canon’s professional 1D mkIV tops out at 10fps and that costs more than three times the A77’s asking price.

A viewfinder revolution

As for the A77’s viewfinder, well, it’s been engineered to rival an optical equivalent: a 2.4 million dot OLED screen with a 1.09x magnification means the screen is large to the eye and the resolution is the highest of any consumer camera product available. OLED (Organic Light Emitting Diode) is also a step ahead of usual LCD technology thanks to a greater contrast ratio, deeper blacks and lower power consumption. In context this means the A77 has the best electronic viewfinder that we’ve seen to date, and yet it’s not a total resolve of the common cited issues regarding electronic viewfinders.

The OLED panel benefits from a progressive scan that does eradicate any possible image tearing that would be experienced from an interlaced signal, but yet the refresh rate isn’t quite good enough to cancel out all ghosting. As the light dims and/or when panning fast you’ll still be able to see a subject’s ‘trace’ in some situations. Though, we must say, this OLED beast is far, far superior to lesser models.

In short the A77’s viewfinder is excellent, but it’s still not 100 per cent there by comparison to an optical equivalent. Extensive use of it may lead you to forget that you’re using an EVF, however, but the moment you go back to a decent optical version and the difference is uncanny. So Sony’s taken a massive step in the right direction, but this bone of contention is still something you’ll need to experience in the flesh (or, perhaps more accurately, weather-sealed magnesium alloy) to help make a decision as to whether the A77 is the right sort of camera for you.

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In support of the EVF is a 3in, 921K-dot LCD screen (not OLED this time) that’s mounted on the rear via a vari-angle bracket like no other we’ve ever seen. At first it appears as though the screen sits below the camera when pulled out, but a secondary bracket means this can then be raised up and the screen can be positioned through any angle. The design cuts away the bulk of plastic that’s usually associated with such a hinged system, so even when it’s sunk into the body it meshes together seamlessly.

Devil in the Detail

Sony’s decision to put a 24.3-megapixel sensor into the A77 certainly raised a few eyebrows upon its announcement. It’s the highest resolution APS-C sized CMOS sensor you’ll find in a camera, and there’s always been an argument both for and against ‘more pixels’.

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Let’s pop on our geek hats for a moment: an APS-C sensor is a given size and so the more microlenses (pixels) squeezed into that space the higher the pixel density and less efficient the sensor, theoretically, becomes. There have been arguments over the years about how many microns a microlens should measure for acceptable image quality, but with so many pixels over the A77’s sensor area we’re looking at less then 4mn which is the lowest you’ll find on any DSLR-like camera (excluding Samsung’s 20.3MP NX200).

Right, geek hats off again. We care much more about the real life results than numerical figures and, in reality, the A77’s images are great. So wipe your brows now and panic not about its detail and sharpness proficiency.

From ISO 100-800 we were very happy with the A77’s results, and while low light work up at 1600 does reveal more image noise, the camera’s still able to maintain good colour and detail. Then there’s a sharper jump into processing issues from ISO 3200 and above that cause detail to diminish and colour to dull, which we’ll put down to the highly populated sensor. The A77 won’t win a prize for best low light performance, and sits a couple of stops behind the likes of the D7000, in our opinion, but it’s still an impressive camera and that super-high resolution will appeal to stock photographers and the like.

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Handheld Twilight, a scene mode as found in Sony’s Cyber-shot compacts, is another way of shooting in low light and certainly shouldn’t be sniffed at. This mode shoots a series of shots in quick succession and merges them for optimum exposure and clarity – and it really works.

Turbocharged shooting

As mentioned, the A77’s 12fps burst mode outperforms, well, pretty much anything else you’d care to throw at it. But before we get ahead of ourselves, let’s review the inevitable caveat: the 12fps mode on the main mode dial auto-selects aperture and shutter speeds for you, so there’s not the ability to take absolute control. Use the camera in its native ‘Hi’ continuous burst and it maxes out at 8fps, but that’s still more than decent for a £1150 camera.

The Sony’s new autofocus system has a 19-point array, where 11 of those 19 points are cross-type with a sensitivity of f/5.6. That means extra sensitivity whether the camera’s rotated in portrait or landscape orientation. The AF system is suitably fast to match up with the 77’s speedy burst mode, and there’s even a subject tracking mode that happily clings on to a target subject to maintain focus.

Movie Magic

All this speed and focusing magic eloquently translates into the A77’s movie mode. As continuous autofocus is possible at all times, this is one of a handful of DSLR-like cameras that will maintain subject focus. It’s magic stuff. What makes the A77 far better than its A35 and A55 siblings is the ability to make the use of multiple AF points or even live subject tracking to great effect.

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The 1080p mode can shoot at 50 frames per second (60 for the NTSC regions) and deliver data at a staggering 28mbps. 25p or 50i modes at 24/17mbps are also available.

It is also possible to manually exposure in any of the S/A/M modes, but only when using manual focus – pop the camera into any other focus mode and it’ll quickly take over all the exposure controls again. Still, this still means the Sony equals, if not outshines, the likes of the Canon EOS 7D on the movie front.

The downsides

But for all its speed there’re a few things that give the A77 a couple of knocks. First of all the time it takes for the viewfinder to activate when approaching it. It’s just far too slow. Sure it’s possible to turn the viewfinder to ‘always on’ but then the LCD screen can’t be used to auto-review images without having to click a further button.

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The same lag is apparent when first turning the camera on – it’s not as speedy to be primed for action as its rivals. We’ve got our fingers crossed these issues can be fixed via a firmware update at a later date.

All this tech is also rather power hungry. While the A77 lasts a decent stretch for most snappers, you’re looking at only about half the battery life compared to more pro-spec rivals. And that may be a significant impact for more serious shooters looking to take hundreds or thousands of shots, though a VG-C77AM battery pack (£279, sold separately) may help to iron out those power woes.


A camera worth waiting for: the A77 certainly puts the SLT format on the map and is a worthy update of the A700. Its fast burst mode, continuous autofocus and solid 24MP image quality are all attractive qualities for an £1150 camera body.

Then add weather-sealing for rugged use, the best electronic viewfinder we’ve yet seen in a camera and an awesome movie mode and the A77’s right to be causing a stir. Sure, the viewfinder situation still won’t meet all demands, battery life depletes fast and the high ISO image quality, while fine, isn’t a match for some other cameras out there.

But there’s little not to like about Sony’s latest. It’s an SLT that could genuinely strangle the DSLR market dominance as it not only matches but outperforms in a number of departments. This is a camera for the new wave of tech-hungry shooters.

Writing by William Perceval.