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The Sony Alpha a57's full-time Phase Detection AF system is excellent, being quick to find a positive lock with a good level of accuracy under decent lighting conditions. The 15-point system - borrowed from the higher-end Sony Alpha a65 - features three cross-type sensors.
You also benefit from the previously mentioned, newly-honed Object Tracking AF feature. This performs well, successfully maintaining a lock on human faces or other subjects moving across the frame, even if they happen to briefly exit the shot or become momentarily obscured by something in the foreground. As the light levels drop, however, the camera does struggle, even with its AF-assist lamp enabled to help it along.
The fast AF system is also of huge benefit when shooting Full HD movies with the Sony Alpha a57. With the option of accessing this feature via the mode dial or a dedicated button on the back of the camera, this easily accessible feature - shot at 50p (progressive) - yields relatively smooth and highly detailed movies, with fairly good sound being recorded by the camera's built-in stereo microphones.
Serious video enthusiasts have the option of plugging in an external mic to improve sound quality further, although a lack of manually-controllable options over this aspect of the video mode may prove to be a little less impressive to some.
Auto Portrait Framing
Auto Portrait Framing is a new feature which Sony claims to be the first of its kind. Face Detection and the tried-and-trusted Rule of Thirds are employed to analyse your portraits, before automatically cropping the frame to perfect the composition.
It could prove useful to those who have trouble achieving balanced compositions when photographing people.
As the name suggest, once you've taken your shot, the camera analyses its composition and applies the Rule of Thirds to automatically correct for any dodgy framing. Once it's finished doing this, the image is then cropped (note that you may end up with the final shot in the opposite orientation to your original, depending on what the camera deems to be the most pleasing).
Next, Sony's other new innovation – By Pixel Super Resolution technology – steps in and resamples the image to recreate a full-resolution, perfectly-framed portrait. Results are generally very good, although the fact that the camera simultaneously saves your untouched, original shots alongside the edited versions provides insurance if you find you're not keen on the A57's artistic interpretation of your photograph.
Clear Image Zoom
The grandly named By Pixel Super Resolution Technology is also employed when using the Sony Alpha a57's 2x Clear Image Zoom, an enhanced alternative to the notoriously destructive digital zoom feature that we've often criticised in the past.
This system differs in that the apparent 'magnification' offered (by cropping into the original shot to give the effect of doubling the longest focal length of the lens) isn't simply left in its low-res state, but rather reconstructed in its newly composed state to create a full resolution image once more.
When it comes to in-camera image customisation features, the Sony Alpha a57 has plenty to offer. As well as useful features such as the previously mentioned Auto HDR, plus DRO (Dynamic Range Optimiser) modes, there's a good range of opportunities to hone the colours and style of your images without having to go near a computer.
Accessed via a shortcut key on the four-way pad or the onscreen Fn menu, a range of Picture Effects - comprising Toy Camera, Pop Color, Posterization, Retro Photo, Soft High Key, Partial Color, High Contrast Mono, Soft Focus, HDR Painting, Rich Tone Mono and Miniature - are available.
Each effect applies a distinctive look to your images, with some providing further options that enable you to dictate how strongly the effect is applied, or to toggle between black and white and colour options, for example.
Some produce more pleasing results than others, but exploring the options and experimenting with settings is a fun way to boost the creative potential of your shots.
Additional control over the appearance of colours, in addition to the overall contrast, saturation and sharpness of JPEGs, can be tweaked in the Creative Style menu (via the Fn button). Here, you can choose from Standard, Vivid, Portrait, Landscape, Sunset or Black and White, with the option to adjust each of the above aspects to perfect the look of your images in-camera.
In Standard mode, by default JPEGs are faithfully coloured and display a pleasing level of sharpness, although shots will take a little extra post-shoot sharpening if you feel the need to boost the detail a little further. Raw files offer further scope for advanced image processing, packing in plenty of detail.
On the whole, the Sony Alpha a57 produces even exposures, but high contrast conditions can trigger a tendency towards under or over-exposure. These issues can be overcome by applying exposure compensation or by experimenting with the aforementioned dynamic range-expanding HDR and DRO modes.
