Sony Alpha SLT-A57

Matching high-speed burst performance with a comfortable, easy-to-use feel, the A57 is a great SLR for most beginner and intermediate photographers.


8.4
CNET Rating

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About The Author

CNET Editor

Lexy spent her formative years taking a lot of photos and dreaming in technicolour. Nothing much has changed now she's covering all things photography related for CNET.


Design and features

Sony's translucent mirror technology is behind all of its Alpha SLRs, including the A57. A special pellicle mirror simultaneously sends light to the image sensor and to an AF sensor, unlike the system that operates on traditional SLRs. This means two things in practice; that translucent mirror cameras can usually shoot faster than their traditional SLR counterparts, and also that the lack of a moving mirror means no blackout time when a photo is taken.

For all intents and purposes, the A57 feels just like any ordinary SLR. It is relatively lightweight and easy to hold in the hand, thanks to a protruding and textured hand grip. Swivel the camera around to the back and you will find a 3-inch, 920,000-dot LCD screen that can pop out and rotate from its base, allowing for overhead shots. Compared to the A55, this camera feels like a much more sturdy and pleasantly-designed photo-taking machine.

Also on the back panel is a pretty standard configuration of control buttons, including an instant-on record button and a four-way directional pad for adjusting focus, white balance, display, timer/burst and creative filters.

The A57 comes with a whole range of connectivity options, which is pleasing to see on a camera of this class, including a microphone jack, remote port, power input jack, HDMI and USB connector. The electronic viewfinder is bright, high-resolution and easy to see.

Inside the chassis, the A57 shares the same 16.1-megapixel sensor as the NEX-5N, as well as a new image processor.

There are a few unique features on the A57, but their usefulness is debatable for photographers. First up is auto portrait framing, which takes a regular shot with a person in the frame and automatically crops in for the most flattering composition (according to the camera, not necessarily to the human eye). Unfortunately, the camera decides to interpolate the missing data that occurs when cropping to give a 16-megapixel image, rather than just leaving the photo at the reduced resolution.

Clear Image Zoom is a tad more useful; it allows the camera to seem like it has a longer optical zoom lens than it really does. Again, the extra data is interpolated here, as not to reduce the effective resolution. This technique is actually called Sony's By Pixel Super Resolution — what a mouthful. The A57 also gets sweep panorama, which automatically stitches together images taken by holding the shutter button down and panning the camera across an axis. In-built HDR features as well.

Like other Sony cameras, image stabilisation is built into the camera body (sensor shift) so theoretically, any lens mounted to the front of the camera will automatically be stabilised.

Compared to

Nikon D5200 Canon EOS 650D Sony A57
24.1-megapixel CMOS APS-C sensor 18-megaxpiel CMOS APS-C sensor 16.1-megapixel Exmor HD APS-C sensor
3-inch, 920,000-dot rotating LCD 3-inch, 1.4-million-dot rotating touchscreen LCD 3-inch, 921,600-dot rotating (from base) LCD
39-area AF (9 cross-type) 9-area AF (all cross-type) 15-area AF (3 cross-type)
Full HD video (H.264/MPEG-4, 1080p, 20/25/24fps) Full HD video (H.264/MPEG-4, 1080p, 30/25/24fps) Full HD video (AVCHD/MP4, 1080i or 1080p)

Performance

General shooting metrics (in seconds)

  • Start-up to first shot time
  • JPEG shot-to-shot time
  • RAW shot-to-shot time
  • Shutter lag
  • 0.30.40.50.1
    Canon EOS 650D
  • 0.30.40.40.2
    Canon EOS 60D
  • 0.30.60.70.3
    Nikon D5100
  • 1.60.50.50.1
    Sony A57

(Shorter bars indicate better performance)

Continuous shooting speed (in frames per second)

  • 12
    Sony A57
  • 5.3
    Canon EOS 60D
  • 5
    Canon EOS 650D
  • 3.8
    Nikon D5100

(Longer bars indicate better performance)

Sony rates the battery at 550 shots when using the viewfinder, and 590 shots when using the LCD screen. The A57 has one of the fastest continuous burst shooting modes available on a camera of this class, if not the fastest. It can shoot at up to 12 frames per second at a reduced resolution of 8-megapixels, with exposure locked at the start of the sequence. This mode is activated from the dedicated option on the mode dial, denoted by the T12 marking.

In regular continuous shooting mode, which records 16-megapixel still images (within the menu system, rather than on the mode dial), the A57 starts to slow down after 25 full-resolution JPEG shots. In this setting, you can achieve around 6 frames of continuous shooting per second.

Image quality

As we've noticed before when testing out other Sony entry-level SLRs, the kit 18-55mm lens is not particularly impressive compared to competing kit models from other manufacturers. It's definitely worth thinking about investing in a better lens to get the most out of the sensor.

Colour rendition is always a strong point for Sony cameras, and the A57 is no exception to this rule when shooting on default settings. The addition of creative filters also strengthens the image-taking base of the A57, particularly for beginner photographers who would rather apply effects in-camera than rely on post-processing. Exposures are generally accurate, if a little conservative by underexposing in certain situations. This is much more preferable to overexposing, and gives photographers much more latitude when it comes to recovering details from highlight and shadow areas.

Click the image for the full resolution crops.
(Credit: CBSi)

The A57 does struggle a little at high ISO sensitivities, notably at those above ISO 3200, where noise does become visible even at reduced magnifications. The camera can hit ISO 16,000, though there's plenty of colour noise and shifting happening at this level, as would be expected. White balance is a little on the warm side when used on automatic settings under artificial lighting conditions, but does an accurate job when shooting in daylight.

Video recording gets an upgrade to AVCHD 2 at 50fps, or MP4 recording if you prefer. Quality is very good, with relatively smooth continuous autofocusing while filming. This can be turned off if desired. The A57 also allows for manual exposure control when shooting video. The stereo microphones record decent audio, though there isn't much separation, due to the units being placed quite close together on the camera body. Best results will always be obtained with an external microphone.

Image samples

Exposure: 1/250, f/8, ISO 100

Exposure: 1/100, f/5.6, ISO 100

Exposure: 1/80, f/5.6, ISO 2000

Exposure: 1/80, f/5.6, ISO 800

(Credit: CBSi)

Conclusion

Matching high-speed burst performance with a comfortable, easy-to-use feel, the A57 is a great SLR for most beginner and intermediate photographers. Skip the kit lens and buy something like a 50mm f/1.8 prime for the best results, until you can afford some more premium glass to get the most out of the sensor.



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