Sony has decided to keep the Alpha 65 and 77 company with a third SLT, the Alpha 57. This latest model is billed as an 'advanced entry-level model', a bit like the Nikon D5100 and the Canon EOS 600D, for example. The Alpha 57 has a 16-Megapixel sensor, a 1.44-Mpt electronic viewfinder (EVF) and, of course, Sony's semi-transparent mirror system that brings an effective continuous autofocus to burst mode and video mode.
The Alpha 57 body isn't derived directly from this camera's predecessor, the Alpha 55, but from the higher-end Alpha 65. The design is therefore less boxy and more fluid—particularly on the upper edge—with a higher grip handle and buttons on the rear face that are easier to access. Grip is therefore improved and the Alpha 57 is generally more pleasant to handle than the Alpha 55, even if some design features still need working on—like the hollow sound of the hard plastics, which doesn't exactly inspire confidence.
The screen has a tilt function thanks to a hinge on its bottom edge. While this can be handy for lining up shots over the top of obstacles, it's still not quite as versatile as the full swivel screens seen in the likes of the Canon EOS 600D and Nikon D5100. Otherwise, the display seems to be lifted straight out of the Alpha 65, but that's no bad thing—it's sharply defined, comfortable to read, has wide viewing angles and reproduces colours well, even if they're a little cold.
The same can't be said for the viewfinder, however. The excellent OLED EVFs seen in the Alpha 65, Alpha 77 and NEX-7 were no doubt too pricey to use in an entry-level camera (although Sony could have used a decent LCD viewfinder—like those seen in Olympus cameras). But while the Alpha 57 EVF has gained in resolution, the image still isn't accurate, with a Delta E of 6.7 and a blue overtone that's actually visible to the naked eye. This is confirmed by a colour temperature reading at over 10000 K when it should be 6500 K. The EVF lacks contrast too, as blacks actually just look like dark grey. Worse still, this viewfinder displays colours sequentially, cycling through red, green and blue alternately. The eye effectively recomposes the image, but if you move your eye around in the viewfinder you may notice a slight rainbow effect due to colour break-up. Not everyone is sensitive to this, but for users who are it can be a real pain.
The graphic user interface is the same as in other recent Sony Alphas, with the same strengths (clear layout), the same debatable features (Fn menu in two columns) and the same incomprehensible elements (the direction of panoramic shots hidden away in the general menu rather than in the Fn menu).
Like other SLT cameras—basically SLRs with an EVF—it's hard to find fault with the Alpha 57 in this field. The one-second start-up is its only relative niggle ... although the whole SLR market is so close on this front that this definitely remains relative!
The autofocus is fast and consistent, photo-to-photo turnaround takes barely longer than the time you'll need to reposition your finger on the shutter-release, and the continuous shooting mode manages 7.5 frames per second, although this can be upped to 12 fps with no autofocus and 8-Megapixel resolution.
[sous_note(811,Qualité des images,,)]
The Alpha 57 has the same 16-Megapixel CMOS sensor that's already been widely used in recent Sony, Pentax and Nikon cameras.
As usual with this sensor, the ISO test results are excellent. Recent Sony cameras have tended to take Jpeg shots that are quite heavily processed, and that's the case here too. Smoothing starts at 1600 ISO, although it's barely visible on full-sized images, becoming heavier at 6400 ISO, which is the highest ISO setting we'd recommend for a decent 8" x 12" print (20 x 30 cm). Textures, however, are preserved more effectively than in the Alpha 57, an improvement we've already seen in this year's Sony compacts. Ultimately, though, users looking for more natural images may prefer the more subtle image processing of the Nikon D5100 or Pentax K-5 ... or they can just use RAW mode and post-edit themselves.
Lens quality obviously depends on which model you hook up to your Alpha 57 body. The Sony 18-55 mm SAM kit lens is well known for its somewhat variable quality. As it happens, the one we were sent did an OK job and didn't come off badly from comparison to Nikon and Canon 18-55 mm lenses, especially at wide-angle settings. However, from experience, we unfortunately know that this may not be the case for all models, as some versions of this lens we've tested in the past have turned out to give below average performances.
One feature that's specific to SLT cameras is that the autofocus sensor is never out of action like in classic SLRs. This brings continuous, automatic and highly effective focusing to the video mode.
The Alpha 57 therefore delivers top-level quality on every front in video mode, with a sharp image, an effective autofocus and 1080p HD resolution at 25 or 50 frames per second, as well as 1080i at 50 fields per second.
Sound quality is decent, with a marked stereo effect, even if it is a little sensitive to echoes and the noise of the autofocus motor—that's with the 18-55 mm lens, of course. If you use a lens with an ultrasonic motor it won't be a problem. Note too that you can hook up an external microphone.