Sony a57 Review (Sony Alpha SLT-A57): System Camera With Ten Frames Per Second

With the introduction of the Sony a57, Sony is once again relying on a strength of SLT technology with its fixed, semi-transparent mirror: at a full resolution of 16 megapixels, the digital camera takes a rapid ten images per second.

This makes it predestined for action shots and for capturing a specific moment of a motion sequence. Even with FullHD video recording, the fast phase autofocus remains active. At a price of just under 750 dollars at market launch (currently it is possible to find cheaper models), it still remains in the attractive segment of hobby system cameras.

Sony a57 Pros And Cons

Pros

• Movably mounted image sensor as image stabilizer for all attached lenses
• High working speed with rapid autofocus and fast continuous shooting
• Comprehensive video functions (P/A/S/M, ISO setting, FullHD@50p, microphone input)

Cons

• Despite a resolution of only 16 megapixels, the set lens provides a mixed image quality
• No configuration possibilities of the ISO automatic
• Unlucky pivot/swivel screen mounting point can restrict freedom of movement on the tripod
• Unlike the previous model no built-in GPS

A new automatic system is designed to help the amateur photographer to achieve professional portraits. The camera places a frame around the recognized face, including the background of the image such as the horizon, and places the frame around the face in the same way a professional photographer would. When the shutter is released, both the original photo and only the contents of the frame are stored on the memory card.

As long as the frame does not cover the entire image field, the camera uses a kind of digital zoom to increase the resolution of the detail back to 16 megapixels. The digital zoom fills in the missing details when zooming in using an internal database with matching structures so that the final result should appear realistically detailed. Even with normal photos, the function called “By Pixel Super Resolution Technology” by Sony is available to digitally extend the limits of the zoom lens.

The Sony a57 not only records ten fast continuous frames per second but also FullHD video at up to 50p and stores it in AVCHD 2.0 format. Alternatively, the videographer can also switch back to 25p if 25 frames per second are sufficient. In continuous shooting mode, a new function allows zooming and exposure adjustment during shooting.

If you reduce the resolution to M (Crop 1.4 with about 8.4 megapixels), the Sony a57 can even achieve twelve frames per second. Functions such as 3D panning panorama, the mechanical image stabilizer by means of sensor-shift, smile release and HDR function are also available.

Creative effects are provided by eleven image processing modes with 15 effects, some of which can even be used in video recordings.

Since April 2012, the Sony a57 is available for 750 dollars. The set with the SAL-1855 (zoom lens with 18-55 millimeters) is 100 dollars more expensive, the double set with the SAL-1855 and SAL-55200 (zoom lens with 55-200 millimeters) brings it to almost 1,050 dollars.

Ergonomics and Workmanship

Although the Sony SLT Sony a57 is the successor model of the Alpha 55V, it looks more similar to the Alpha 65V because it has its case. It is made of plastic but is solidly processed, the gap dimensions are small.

The case is a bit larger than that of the Alpha 55V and therefore, the Sony a57 lies somewhat better in the hand. Large leather-like rubber applications are used on the handle as well as in the area of the thumb cavity, which increases the grip of the camera.

The trip unit and the closing lever arranged in a ring around it are now in the same color as the casing. The shutter release has two defined pressure points and can be operated unerringly without getting used to it.

Underneath it is a dial that you would normally operate with your index finger. However, since the camera has only one dial, the aperture must be changed in manual mode by holding down the AEL button and pressing the dial at the same time.

At the very least, it is unusual to use this button for this purpose (instead of the exposure-compensation button, which is also functionless in manual mode).

Once you’ve gotten used to it, however, it works quite well, as the AEL key is perfectly accessible for the thumb. The same applies to the remaining ten buttons to the right of the display, which are within thumb reach.

The dominating element on the back is the three-inch (approx. 7.6 centimeters) large turn/swivel screen. It has a fine resolution of 921,000 pixels and is anti-reflective, which means that it can at least be read in bright ambient light.

The display is very well suited for shots close to the ground or overhead, but shots in front of the stomach in “light well style” are also possible. The display is also great for self-portraits, as it looks out from under the camera and sits quite close to the lens.

It becomes more problematic if you want to turn the display when the camera is mounted on a tripod. Here the display can sometimes come into the enclosure with the tripod due to the joint at the bottom.

But it is also possible to fold the display backwards to the camera, then it is well protected and you can use the viewfinder. Here, however, you are not looking at a ground glass screen but at an electronic display with 1.44 million pixels, of which about 1.32 million pixels are used in the native 3:2 format.

The viewfinder image is bright and has a fine resolution, but it is somewhat lacking in contrast and – much worse – it shows a clear blue cast, so that, for example, a red roof can go into the purple compared to the display.

Conveniently, the viewfinder has a proximity sensor and therefore automatically turns on when you approach it and the display goes off.

The Sony a57, like every camera with SLT technology from Sony, has a special feature: The mirror is rigidly mounted and directs about two-thirds of the light to the main sensor, while one third ends up on the autofocus sensor.

It has 15 measuring fields, which function as phase sensors like any SLR camera. This gives the Sony a57 a fast and very accurate autofocus that works without pumps – even in video mode. Even with the set lens, the camera only takes a good quarter of a second to focus and release, making it one of the fastest cameras in its class.

On the left side, the Sony a57 is littered with connections, in detail: HDMI, cable remote release, mains connection, USB and microphone (including phantom power). The memory card, however, is located on the side of the handle.

The dual-slot accepts either a Memory Stick Pro Duo or an SD card, with compatibility to SDHC and SDXC also given. The lithium-ion battery can be removed at the bottom. It is sufficient for 550 to 590 photos according to the CIPA standard (with screen usage it is a little less than with the electronic viewfinder), which is a good 200 photos more than with the Alpha 55 – a clear plus point for the Sony a57.

Practical too: the battery level is displayed on the screen with a precise percentage. The metal tripod thread on the bottom is located in the optical axis, the distance to the battery compartment allows the battery to be changed even with a normal-sized tripod changing plate.

Numerous functions can be operated directly via buttons on the camera. Pressing the Fn button calls up a quick menu in which further recording parameters can be set.

Because ISO, white balance, continuous-advance, and self-timer are on dedicated buttons, you only need to enter this menu for more specialized functions such as HDR, metering, or creative mode.

The only downer: The flash setting is also “hidden” here. Fortunately, the ISO and AEL buttons can be programmed and assigned to other functions, such as the flash setting. The main menu is also clearly laid out and a help button displays explanations if necessary so that if you are a photographer with some experience, the Sony a57 does not necessarily need the manual.

Equipment And Features

The Sony a57 offers just about everything that both beginners and advanced photographers can expect from a system camera.

Two fully automatic modes make it easy to get into the picture and use the camera for those who only understand “aperture”, “ISO” and “exposure time”. If desired, the camera recognizes the subject and sets all parameters automatically, even the flash pops up automatically if necessary. You can also get creative with the image effects, which can be varied in many settings.

The Alpha also has ready-made scene mode programs, which can be specifically set by the user. Those who dare to manually preselect exposure time or aperture or even want to expose correctly manually will get their money’s worth with the classic exposure programs P, A, S and M. Of course, the Sony also records in RAW format on request, either instead of or in addition to JPEG.

The user can also unfold his creativity in video mode, like ISO, exposure time and aperture are also manually adjustable here.

However, if you select the aperture and/or exposure time manually, you must necessarily switch off the autofocus; the maximum ISO sensitivity is then 3,200 instead of the 16,000 available for photos.

Although the Sony a57 has a dedicated video recording button so that a movie recording can be started in any mode, it also has a position for video on the program dial. Here you can access the manual film settings and the viewfinder image is then also in 16:9 aspect ratio.

The Sony a57 has an internal stereo microphone, but if you don’t want noise from the camera on the audio track, you should use the external microphone connection option. The video resolution is 1,920 x 1,080 pixels and thus corresponds to FullHD, the frame rate is selectable between 25p, 50i, and 50p, stored as AVCHD.

If you change the file format to MP4, the resolution drops to 1,440 x 1,080 pixels, and VGA resolution (640 x 480 pixels) can also be selected here if desired. By the way, the image stabilizer during filming works purely electronically, which means the loss of some picture angle as a reserve for the stabilization.

This is completely different in the case of photos, here the internal image stabilizer is active by means of a movably mounted sensor. It works effectively and above all with an attached lens so that the image stabilizer is also available with fast fixed focal lengths, wide-angle lenses, etc., which are not normally available in a stabilized version.

Incidentally, the DT 18-55 mm 3.5-5.6 SAM set lens used in the test does not quite do justice to the housing quality of the Sony a57; it looks cheap, which is underlined by the plastic bayonet and the front lens that rotates with the focus, together with the filter thread.

Fortunately, Sony offers a rich lens program from the cheap but quite good fixed focal length up to high-quality zooms or fixed focal lengths. But the set lens is always enough to try out and gain experience so that you can add better lenses to the camera later.

By the way, the Sony a57 offers all kinds of special programs designed to help in difficult situations. The Dynamic Range Optimizer DRO, for example, is designed to help master high-contrast subjects better by adjusting the tonal values: The shadows are a little brighter, the lights a little darker, to make more drawing visible.

This works even better with the built-in HDR function, which takes differently exposed photos and automatically compensates for them – even a slight image offset is detected and compensated.

For static scenes an excellent solution that does not require any software on the PC. If you don’t have a tripod with you and still want to shoot a night scene with a slow shutter speed, the Alpha also has a solution: it takes several short exposures and superimposes them with a perfect fit, resulting in an unshaky image. The swivel panorama, optionally even three-dimensional, is also practical. The camera takes photos in quick succession when you pan and automatically composes the panorama.

The rapid continuous shooting function with up to ten frames per second helps her do this; with slight image cropping, even twelve frames per second are possible in a special program for action shots.

Sony, on the other hand, saves on the image editing options after the picture has been taken. Here, there are no subsequent effects, filters and suchlike that are so numerously found for example at Pentax or Nikon.

Another useful function has even fallen victim to the red pencil: The absence of the “V” in the camera name already indicates that the Sony a57 does not have built-in GPS.

Although we criticized the reception quality and speed with which the GPS worked on the Alpha 55, leaving it out altogether is not an elegant solution. Postponing photos never hurts and is sometimes extremely useful, as it allows you to determine the exact location of the photo.

Image Quality Of The Sony a57

With its 16 megapixel resolution, the Sony a57 seems almost modest, as there are already some cameras with 24 megapixels on an APS-C sensor. However, the “only” 16 megapixels also offer advantages: lower noise and a higher dynamic range can be expected due to the larger area per pixel, and 16 megapixels are completely sufficient even for large photo prints in DIN A3 and more.

The Sony a57 does not disappoint the assumptions: Up to and including ISO 400, it shines with a good signal-to-noise ratio of over 40 dB, up to ISO 1,600 it remains in the acceptable range of over 35 dB, but at higher sensitivities, adjustable up to ISO 16,000, the signal-to-noise ratio drops to poor values.

Up to ISO 400, noise is fine-grained but becomes coarser with each ISO level. From ISO 6.400 on, the graininess decreases abruptly, and a powerful camera-internal image processing visibly increases here. The brightness noise is low and rises very slowly; it only becomes visible at ISO 6.400. Color noise is only slightly noticeable at the highest sensitivity of ISO 16,000.

The Sony a57 up to and including ISO 800 reproduces fine textures in great detail, and even at ISO 1,600, there is hardly any visible soft-focus effect of noise reduction.

This only changes from ISO 3.200 onward, and towards ISO 3.200, the detail rendition decreases even more noticeably; here, too, the stronger noise suppression becomes apparent from this ISO value onward. Up to ISO 16.00, the Sony a57 then moves into the visibly softer range in terms of detail reproduction.

However, it does not advance into the very blurred area. The dynamic range is up to ISO 1,600 at high 10.7 f-stops and is still good at ISO 3,200 with ten f-stops. Afterward, it drops to only satisfactory nine to eight f-stops, but again no critically bad values are achieved.

The tonal value curve shows a divided course, thus the camera reproduces brightness values more contrasty and beautified, which subjectively provides a crisp impression.

Brightness values are finely differentiated up to and including ISO 400, but then the gradations begin to become coarser. At ISO 800, more than 190 of 256 steps are still possible, at ISO 1,600 there are still a good 170 steps. But then the camera sinks into the worse range, at ISO 6.400 and higher, the brightness values are even less than 100.

It looks a little better with the color depth. Again, up to ISO 400, the best values are achieved with over eight million colors, up to ISO 3,200 the A57 remains good with over three million colors, but at higher ISO levels, only under two million colors are differentiated.

The manual white balance works precisely, the color reproduction is still okay on average, but some colors deviate more, for example, the more saturated red tones, but there are also deviations in the yellow and violet area. All in all, this gives the pictures a pleasantly warm character.

Up to ISO 400, the Sony a57 can thus be certified as having excellent image quality, but up to ISO 1,600, it is still very good. There are some limitations on this, although the noise reduction tries to hide this. But this mainly reduces the detail drawing.

However, the set lens is problematic. It registers quite strongly in wide-angle with about three percent barrel shape, and the resolution is also limited at the edges of the image. This even applies to the longer focal lengths.

Fading down to F8 generally helps if you want reasonably sharp pictures right into the corners. Color fringes also appear and only become smaller at aperture F8. All in all, the set lens thus significantly limits the Sony a57’s image quality, so that one should look around for high-quality alternatives. The 18-250 mm from Sony, which we also subjected to analysis with the test software on the Sony a57, lends itself as a travel lens.

The 18-250 also shows edge blurring, but this is mainly seen at wide-angle, at aperture F5.6 it gets better. Overall, however, this lens has a moderate resolution over the entire focal length range, which is still sufficient for photos measuring 20 by 30 centimeters, but nothing more.

Also with the 18-250 one has to expect strong distortions, but the strong barrel shape in the wide-angle is joined by a visible cushion shape in the telephoto range. Especially chromatic aberrations are unpleasantly noticeable here, which don’t quite come to the fore at the wide-angle and medium focal length.

Good alternatives to zooms are generally fixed focal lengths, with the 50 mm 1.8 SAM we have tested a cheap one. The lens shows a better imaging performance than the zooms, so it has very little barrel distortion and shows only slight color fringing.

The resolution is sufficient for 20 x 30 centimeters with all apertures, especially the resolution at the edge of the image is equal to that in the center. For higher resolution, however, the lens should be stopped down considerably, from F5.6 to F8 it reaches a good resolution, the best at F11, above that diffraction strikes.

Conclusion: Is The Sony a57 Worth It?

The  Sony a57 can convince as a complete package, as it only shows minor weaknesses in the test. The video function is comprehensive, and the speed is outstanding not only for its class. Even the workmanship of the plastic housing is impeccable.

In practice, the extremely useful swivel screen has the shortcoming of hinge placement, which can restrict freedom of movement on the tripod.

Sony could also make the ISO automatic even more configurable and there is still a big gap in the camera’s internal image processing options. In terms of image quality, the Sony a57 is once again convincing, among other things with low image noise.

However, the weak 18-55 mm SAM set lens noticeably limits the picture quality, so the demanding buyer should look for alternatives.

Sony a57 (Alpha SLT-A57) Datasheet