Sony Alpha 58 at a glance:
- 20.1-million-pixel, Exmor APS HD CMOS sensor
- 1.44-million-dot OLED electronic viewfinder
- Sony Alpha mount
- Sensor-shift stabilisation
- Tiltable 2.7in, 460,800-dot TFT screen
- Up to 8fps shooting rate
- 1080p HD video capture
- Street price around £430 with 18-55mm f/3.5-5.6 kit lens
Sony Alpha 58 review – Introduction
Like all Sony DSLR-style cameras we have seen since the launch of the Alpha 33 and 55 in 2010, the Alpha 58 is based around the company’s translucent mirror technology, in which the moving mirror and pentaprism found in a typical DSLR are removed and replaced with a fixed, semi-transparent mirror. With roughly two-thirds of the light that comes through the lens travelling on through the translucent mirror to the sensor, the other third is bounced up to the AF sensor. The benefit of this is that autofocus can remain in action even when a shot is fired – on a traditional DSLR, the mirror is raised and AF is interrupted very briefly when the shutter is triggered – while the burst frame rate can also be improved over DSLR rivals. The absence of a pentaprism does, however, see the optical viewfinder substituted for an electronic equivalent.
The Sony Alpha 58 features a completely new 20.1-million-pixel sensor, but with some established leaders in this sector, does Sony’s new model offer the photographer enough to stand out from the crowd?
Sony Alpha 58 review – Features
Rather than opt for the 24.3-million-pixel sensor found on Sony’s higher-end SLT cameras, Sony has developed an all-new, 20.1-million-pixel Exmor APS HD CMOS sensor that improves on the 16.1-million-pixel Exmor APS HD CMOS sensor used by both the Alpha 37 and 57. There is also a new and improved Bionz image-processing engine that individually adjusts levels of noise reduction and sharpness in different imaging areas, while the ISO sensitivity is good for a camera in this class at 100-16,000.
The electronic viewfinder is a 1.44-million-dot OLED device with Tru-Finder technology. This improves on the LCD display found in the Alpha 57, reducing overall power consumption, while the 100% field of view offered is better than most DSLRs at this price point.
Interestingly, the rear screen has shrunk in size since the Alpha 57, with a 2.7in, 460,800-dot display now in place compared to the 3in, 921,000-dot screen on the previous camera. The screen can be pulled out and angled for shooting at different heights, but because its hinged differently to that on the Alpha 57, it doesn’t offer quite the same breadth of movement.
The AF system builds on the system used in the Alpha 57. The 15-point AF arrangement, of which three are the more sensitive cross-types, is in place in the Alpha 58, which also benefits from a new lock-on autofocus technology for what is claimed to be speedier, more accurate subject tracking.
As mentioned, one of the main advantages of Sony’s SLT technology is the ability to shoot a faster frame rates compared to rivals, so its no surprise to find that the Sony Alpha 58 is capable of shooting at up to 8fps. This is a little deceptive, however, with 8fps only possible using the camera’s dedicated Tele-zoom Continuous Advance Priority AE mode. This sees the image cropped by 2x (with the centre of the EVF view automatically magnified), the resolution dropping to a lowly 4.9 million pixels, and the restriction of being able to shoot JPEGs only. Not only is this slower than the all-out pace of the Alpha 57, which could shoot at up to 12fps in Tele-zoom Continuous Advance Priority AE mode, the Alpha 57 is also, more tellingly, capable of shooting at 10fps at full resolution compared to 5fps for the Alpha 58.
Auto Object Framing technology is included in the Sony Alpha 58, which builds upon the Auto Portrait Framing feature first introduced in the Alpha 57. Set to this mode, Sony claims that the Alpha 58 will consider what is in the scene – including people, and close-up and moving subjects – before tracking, framing and cropping the shot for ‘powerful, professionally framed compositions’. Any cropped images are automatically boosted back to the camera’s native resolution using Sony’s By Pixel Super Resolution technology, with both the original and recomposed files saved.
Sony Alpha 58 review – Build and handling
While the exterior construction of the Alpha 58 is predominantly plastic, it is more than satisfactory for the job, though it’s a little disappointing to see a plastic lens mount replacing the more durable metal lens mount found on the majority of DSLRs – including the Alpha 57.
Otherwise, the exterior design of the Alpha 58 is pretty much identical to that of the Alpha 57. In the hand, and thanks to a substantial grip with a pleasing rubberised surface that features depressions for both middle and ring fingers, it provides a comfortable grip and is probably the best in its class.
Overall, the Alpha 58 is fairly straightforward and quick to use. This is in part thanks to the selection of body-mounted controls that provide quick access to ISO, exposure compensation, drive mode and AF. An Fn button is also present, which offers further access to other key shooting controls, while navigation of the camera’s interface is carried out via the four-way D-pad on the rear.
One annoyance concerns raw shooting, which, as with previous Alpha models, is restricted by some of the camera’s modes – for instance, its not possible to shoot with any of the picture effects when shooting raw + JPEG. It would seem that the Alpha 58 simply wants the user to shoot JPEG-only. A warning pops up on screen, but it can only be changed manually by going through the main menu. This is a little frustrating, given that rival models are happy to shoot in similar modes to produce an altered JPEG file and an untouched raw file that can be revisited later.
Shooting at full resolution, the Alpha 58 is capable of shooting 10 JPEGs or 6 raw files at a maximum burst rate of 5fps – however, even with the Alpha 58’s increased resolution over previous models, we would have expected longer bursts than this, while in Tele-zoom Continuous Advance Priority AE mode at 8fps, the Alpha 58 is only capable of producing a burst of 19 frames before it slows down.
Sony Alpha 58 review – Metering
Image: The Alpha 58’s 1,200-zone evaluation metering system has coped well with this challenging scene
The Alpha 58’s metering system is very good, and features a choice of multi-segment, centreweighted or spot metering modes, calculated via the camera’s 1,200-zone evaluative metering system. In our tests, the multi-segment metering performed well, exposing well for most scenes, though on occasion in bright situations it did have a slight tendency to underexpose the shot, requiring a touch of exposure compensation to rectify.
Sony Alpha 58 review – Autofocus
Image: The Alpha 58 has 15 picture effect filters that can be applied to images, though only when shooting JPEGs
The Alpha 58’s AF performance is good for a camera in this class, with speedy AF most of the time, especially using one of the three cross-type points, only hunting in low-contrast situations. One niggle is the grouping of the AF points, seeing a bias towards the centre of the frame, which often results in the need to focus and then recompose if the subject is positioned towards the edge of the frame.
The Alpha 58’s SLT technology means it is able to utilise its 15-point phase-detection AF system during live view and video recording, rather than having to rely on slower contrast-detect AF as most DSLRs do. It therefore delivers the same level of performance via live view as it does when using the viewfinder.
Sony Alpha 58 review – Dynamic range
When shooting JPEGs, I would recommend activating the Alpha 58’s DRO feature to lift shadows for a more balanced exposure in scenes with high contrast. Thanks to the camera’s solid metering performance, blown highlights don’t tend to feature in balanced conditions, while those shooting raw are able to recover any that do in harsher lighting conditions using raw-conversion software. It is a similar story when shadow detail needs to be recovered.
Sony Alpha 58 review – Noise, resolution and sensitivity
These images show 72ppi (100% on a computer screen) sections of images of a resolution chart, captured using the Sigma 105mm f/2.8 Macro lens. We show the section of the resolution chart where the camera starts to fail to reproduce the lines separately. The higher the number visible in these images, the better the camera’s detail resolution at the specified sensitivity setting.
The new 20.1-million-pixel sensor delivers very good levels of detail. It can resolve to around 28 lines per mm (lppm) at ISO 100, only tailing off to just over 22lpmm at its highest ISO of 16,000, which compares favourably to its rivals.
At its base ISO of 100, images from the camera are virtually noise-free, though subtle signs begin to appear at ISO 800. Above that, the gritty texture of noise appears in raw files at ISO 1600. This increases further as the sensitivity is increased, with luminance noise compromising fine detail and chroma noise deteriorating the image. This is to such an extent that I’d think twice about shooting at ISO 6400 and above, with the Alpha 58 displaying noticeably more image noise than its rivals at identical sensitivities.
The Alpha 58 tries to combat this when shooting JPEG files at these higher sensitivities, but the camera’s in-camera processing delivers mushy-looking files with considerable loss of detail.
Sony Alpha 58 review – White balance and colour
The Alpha 58’s auto white balance performs consistently, delivering pleasing results and natural skin tones under a range of lighting conditions that it was tested in. There’s also a host of presets to dabble with as well, though for most conditions the AWB setting copes admirably.
Sony Alpha 58 review – LCD, viewfinder and video
The electronic viewfinder is a lot less tunnel-like than its optical peers, while there’s a host of shooting info displayed on screen and the 100% coverage means nothing creeps in at the edges of the frame once you’ve taken the shot. Its more than fine for composition and focusing in most situations, but it does struggle with high-contrast scenes and I’d recommend trying it out before buying.
The downgraded rear LCD screen is disappointing, not offering quite the same level of detail and ‘bite’ as the competition or its predecessor, while the tilt-only screen doesn’t off the same breadth of movement as the Alpha 57.
For general video shooting, the Alpha 58 is fine, with the option to shoot at 25p or 50i in AVCHD, while the onboard stereo microphones deliver reasonable sound – though I’d recommend against using the 18-55mm kit lens in AF while recording, as the AF noise from the lens can disrupted audio.
Sony Alpha 58 review – Our verdict
In a tough sector, having a unique selling point is key, and that is what has made Sony’s series of SLTs stand out from the crowd. But with the Alpha 58, its advantages have been diluted quite a bit.
The 20.1-million-pixel sensor sees it resolving greater levels of detail than its siblings, but the results are compromised at high ISO and are not as useable as images from rival models. Factoring in the smaller screen and plastic lens mount, the Alpha 58 seems a step back from the Alpha 57 it replaces. With such stiff competition in the shape of the Canon EOS 600D, Nikon D3200 and Pentax K-30, it’s hard to recommend the Alpha 58 above them.