After a four-year wait, Sony has returned to the enthusiast/semi-pro
end of the DSLR market. Having made little impact in that market with
the A700 that very closely resembled the conventional DSLRs made by
Canon and Nikon, Sony has spent the intervening time developing
something a bit different. The A77 builds on the company's 'translucent
mirror' technology, and uses an electronic rather than optical
viewfinder. The final result is a product that may look traditional, but
is able to promise the unconventional.
Spec-wise the A77 is impressive: it features a new 24MP APS-C CMOS
sensor, 12fps full-resolution shooting and the highest resolution EVF
we've ever encountered (a 2.4M dot OLED finder). It also uses a new
19-point AF sensor, 11 points of which are cross-type (sensitive to
detail in both the vertical and horizontal axis). Clever use of the main
sensor's live view allows the A77 to track objects as they move across
the frame, enabling the camera to have a better understanding of which
AF point it should be using at any given time.
Last year's SLT-A55 gave some clues about how Sony hoped to bring its
electronics know-how to bear in a high-end camera. Its fixed,
semi-transparent mirror design meant Sony could do away with a
conventional optical viewfinder and use an electronic display. It also
meant that the phase-detection autofocus that gives DSLRs much of their
immediacy could be used all the time. The result was a camera that could
shoot at an impressive 10fps, could focus quickly in video mode and
offered full-time live view with consistent DSLR-like behaviour in a way
that no camera had really managed before.
Unsurprisingly the A77 takes all these capabilities a lot further
than the consumer-level A55 - it combines the latest processor with an
electronic first curtain shutter to offer the level of responsiveness
the more demanding enthusiast/semi-pro users will expect. The A77's
massively improved viewfinder is also key to ensuring the A77 can hold
its own against the very stiff competition it faces from the likes of
Canon's 7D. (You don't have to read particularly far between the lines
to conclude it was this feature Sony wanted to perfect before launching
an SLT into this market.)
And, as with the A55 and a handful of other recent Sony cameras, the
A77 offers in-camera GPS. It can be a really useful feature for
organising and retrieving images, as allowing tagged images to be
geo-located on sites such as Flickr.
In addition to the technological advances, Sony has clearly been listening to its audience when developing the camera's firmware - the A77 is not just the most customizable Sony we've ever encountered, but it includes a full quota of high-end features. This includes the ability to fine-adjust the AF tuning, and to define the upper and lower extremes that the Auto ISO system will use - features we've not seen on a Sony camera since the DSLR-A850. Sony SLT-A77 key features:
SLT-A77 and A65 key differences
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FlashThe SLT-A77's built-in flash is pretty standard fare for a camera of this type and at this level. With a guide number of 12m (at ISO 100) It is powerful enough for close-quarters shots and occasional service as a 'fill in' unit but for more serious work you will have to invest in one of Sony's (excellent) external flash guns. If you do so, you might be pleased to learn that the A77's built-in flash can act as a wireless trigger, making it possible to easily create off-camera flash shots which would traditionally have required a cable.
JPEG Sharpness settingsNaturally, whether or not the A77's default sharpness settings are too soft for you depends primarily on what you need your camera to do. If you don't need to make large prints, and you're not inclined to look at your images critically at 100% on screen there is no need to meddle with the A77's parameters. If, however, you want crisper results straight from the camera, a little time experimenting with the A77's JPEG sharpening parameters may prove to be time well spent (even if it's no substitute for careful raw processing).The A77 has seven sharpness parameters, from -3 to +3, with the default being '0'. Of all the settings, we keep coming back to +1. This setting lends JPEGs a pleasant crispness, but avoids the 'crunchiness' characteristic of oversharpening which is apparent in images shot at the +2 setting. If you'd prefer to manage your own sharpening post-capture though, experiment with shooting at sharpness level -2. This is a good starting point for applying your preferred sharpening settings, and images shot at this setting contain no less detail than images taken at any of the A77's other sharpness settings (the detail is simply softer).
Overall image qualityIf you're interested in the A77 because you want excellent critical image quality, and you want to get the absolute most resolution possible out of its 24 million pixels, you already know that you're going to have to shoot in raw mode. If you know what you're doing, and you're prepared to spend a little time doing it, you can get results out of the A77's raw files which at least rival the resolution we'd expect to get out of cameras like the Canon EOS 5D Mark II, and the venerable Sony Alpha 900. At least up to ISO 1600. Beyond this point it becomes progressively more difficult to 'rescue' the A77's raw output due to elevated chroma noise levels.Likewise in JPEG mode, noise is unlikely to bother you until you hit ISO 800-1600. It is present in images shot at lower sensitivities, and you can see it on close inspection in areas of plain tone (especially blue skies) but it really isn't obtrusive, thanks in part to the smoothing effect of in-camera noise reduction. What might bother you, depending on how critically you like to look at your photographs, is the A77's mushy JPEG rendition, which really doesn't show off the sensor's abilities.
Obviously 100% on screen is not necessarily the most sensible way to assess overall image quality from a camera with such a large pixel count. Ultimately, the A77's image quality will keep most people perfectly happy most of the time. It is a disappointing, nonetheless, to see just how much more detail can be drawn out of the A77's raw files compared to its JPEGs, and to see high ISO raw files so bady degraded by noise. GhostingThere was a lot of discussion when the A55 was released of an issue known as 'ghosting'. This was evident in early SLT cameras, and took the form of faint 'ghost' images of bright highlights in some images. Most of the time ghosting was completely invisible, but we did find a few examples amongst our thousands of test shots which exhibited the phenomenon - caused by internal reflections inside the SLT mirror.
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Shadow NoiseThe Sony A77 uses a newly developed 24MP CMOS sensor. This follows on from the last-generation 16MP sensor which has impressed us greatly in the original SLT-A55, the Nikon D7000 and the recently-reviewed NEX-5N. As we can see from the example images below, all taken at base ISO, at a pixel level the A77 is a close match for the Nikon D7000 (and by extension all of the cameras which use the same sensor - the A55, Pentax K5 and Sony NEX-5N amongst others) but slightly superior to the older Canon EOS 7D. You can clearly see that shadow areas in our sample scene which are contain detail in the A77 are becoming 'blocked up' in the 7D, and detail in colored areas is visibly better defined.This might seem like extreme pixel-peeping and of course in a way it is, but there are practical ramifications. It means that you can draw more detail from the shadow areas of the A77's raw files than you might expect from older DSLRs (like the A700), and with less of a penalty in noise (remember the images below were converted from raw files with Adobe Camera RAW NR turned off). Accordingly, you can use functions like Sony's Dynamic Rage Optimization (DRO) confident that you won't give shadow noise an unpleasant boost. Compared to Canon EOS 7D (18MP) @ ISO 100
Compared to Nikon D7000 (16MP) @ ISO 100
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