Sony SLT-A58 review

The vast majority of SLRs we see on the street bear Canon or Nikon logos. Sony clearly wants to change this, and by our reckoning it’s going about it the right way. Digital SLR technology is mature and refined, and ultimately there’s little to choose between similarly priced Canon and Nikon models. Sony, on the other hand, provides some genuine choice with cameras such as the new Sony SLT-A58.

The new camera isn’t a straight replacement for either the A57 or A37

Its SLT cameras aren’t technically SLRs. They use a translucent, non-moving mirror that passes light simultaneously to the main sensor and the autofocus sensor. This has various repercussions, but it allows for fast continuous shooting with full-time autofocus, plus it delivers responsive autofocus while recording video.

FINDING A VIEW

Its viewfinder is electronic rather than optical, which won’t please purists, but an electronic viewfinder (EVF) has its advantages. It means the viewfinder can overlay lots of information, and it can also provide a preview of exposure and white balance settings. The large, high-resolution displays used in Sony SLTs are a million miles away from the poky EVFs found in most ultra-zoom cameras.

Sony’s SLT technology continues to make a persuasive alternative

Perhaps the most significant difference for people upgrading from a compact camera is that the main autofocus system is available when composing shots on the LCD screen. With a true SLR, live view requires the camera to switch to a slower, secondary autofocus system.

The A58 replaces both the entry-level Sony SLT-A37 and its pricier sibling, the A57. It’s not the straightforward upgrade to the A57 that the name suggests, though.

The A57 had a 3in, 921,000-dot screen that could twist and pivot to face almost any direction. The A58’s screen is smaller and coarser at 2.7in and 460,000 dots, and tilts up by 90 degrees and down by 45. Considering how well this camera’s live view mode performs, it’s an odd place to be cutting costs. At least this screen is sharper than the A37’s 230,000-dot screen. Viewing angles could be better, with skewed colours when viewed from above, but the tilting design should mean that this isn’t an issue in practice.

The previous models’ viewfinders were LCDs but the new one is an OLED. This should give deeper contrast, although without comparing them side-by-side we can’t say for sure. It has the same 1,440,000-dot resolution as before but it’s physically smaller (with a 0.88x magnification, down from 1.09x on the A37 and 1.04x on the A57). A big viewfinder makes a huge difference, and this was a big selling point for previous SLT cameras. Still, the 0.88x magnification is on a par with the optical viewfinders in Canon and Nikon’s SLRs at this price. Comparing the A58 with a Nikon D5200 at matching focal lengths, text was very slightly more legible through the D5200’s viewfinder. However, focusing manually was easier on the A57, thanks to a 2x digital zoom function and a focus peaking display, which highlights sharply focused parts of the scene.

PIXELLATION

The 20-megapixel resolution is a significant jump from the 16-megapixel A37 and A57. We’re happy to report that noise levels haven’t increased as a result. If anything they’re marginally lower than from the A37. Continuous performance has taken a hit, though. Full-resolution shooting is at 5fps, down from 10fps on the A57 and 5.5fps on the A37. It’s still not a bad result, but no longer significantly better than the competition.

Composing on the screen is straightforward thanks to the translucent mirror inside

As with its predecessors, there’s a speed-priority mode that manages faster performance – in this case 8fps – complete with continuous autofocus, but the image is cropped to a 5-megapixel central portion of the frame. It could be useful for capturing distant wildlife, but it’s a big step down from the A57’s 12fps, 8.4-megapixel mode.

The controls are virtually indistinguishable to the A57’s, with just a couple of button locations swapped around. It’s a good system, with dedicated buttons for many key functions, plus a Fn button that reveals a quick-access menu. We wish that JPEG and raw settings were accessible via the Fn button, but otherwise the controls are straightforward and effective.

Sony’s proprietary hotshoe has been replaced by a design that virtually all other camera manufacturers use. In fact, it’s actually yet another new proprietary design, called the Multi Interface Shoe, but because it’s based on a standard design, it can accommodate generic accessories such as wireless flash triggers.

The autofocus sensor is the same as on the A37 and A57, with 15 points including three cross-type points for increased sensitivity. That’s a decent specification for the price, but the layout of points felt a little sparse when using the improved subject tracking mode. The camera accurately tracked moving subjects around the frame, but when they moved into an area that wasn’t covered by an autofocus point, the focus couldn’t be updated.

VIDEO AND iSWEEP

The A57’s 1080-50p video mode has been dropped, leaving a choice of 25p or 50i. It’s an odd decision but no great loss for the majority of people. It’s still one of the best video modes to be found on an SLR-like camera, with responsive autofocus and manual exposure control – although frustratingly, not at the same time. The focus motor was clearly audible on the soundtrack, but a microphone socket provides a workaround. Picture quality was generally excellent but details looked a little coarse compared to the Nikon D5200’s videos.

An Auto Object Framing mode intelligently crops photos to create what the camera deems to be better compositions. The original is saved too, and it’s easy to turn this mode off if you don’t like the results. iSweep Panorama makes another appearance, allowing users to capture a high-resolution panoramic image by slowly turning the camera. 3D panorama capture has been quietly dropped, though. A Dynamic Range Optimisation feature lifts the brightness of shadows a little, and it’s useful to see a quick before-and-after directly after capture. HDR shooting is well implemented too.

IMAGE QUALITY

One downside of Sony’s translucent mirror technology is that less light reaches the sensor. On previous models this has meant slightly higher noise levels than in rival SLRs. It was less of a concern this time around, though. The A58 uses strong noise reduction at fast ISO speeds, resulting in low noise but also a slightly glossy sheen with suppressed subtle details. However, comparing our ISO 6400 and 12800 studio test shots with rival SLRs from Canon, Nikon and Pentax, there was no sense that the A58’s JPEGs were obviously inferior. Comparing their unprocessed raw output revealed a more discernible difference, though, with the A58 at ISO 6400 being broadly equivalent to its rivals at ISO 12800.

There’s very little evidence of noise in this ISO 1000 shot, and still plenty of definition in the skin texture

Shaded skin textures are still perfectly acceptable at ISO 2500 – an excellent result

Comparing the unprocessed raw output at ISO 6400 with the 24-megapixel Nikon D5200 shows that the A58’s underlying noise levels are a little higher

Details in bright conditions were crisp and natural, without any halo-like artefacts of heavy digital sharpening. Developing raw files in Lightroom gave a slight improvement to the fidelity of fine details, but the 20-megapixel resolution ensured that JPEGs were far from lacking. The kit lens suffered from poor corner sharpness when photographing nearby subjects, but in most tests it performed well.

The 20-megapixel resolution, reliable autofocus and natural-looking details in JPEGs mean there’s more than enough detail for big prints

Macro shots with the kit lens were less successful, though – this was one of our better results

CONCLUSION

Sony’s choice of model name makes this is a slightly confusing update. In many ways it’s a downgrade from the A57, but it also costs less. Consider it as the successor to the A37, a replacement for an older Sony Alpha or a first SLR-like camera, and it looks more tempting.

Our only real complaint is that Sony isn’t making the most of its SLT technology. The viewfinder and LCD screen are smaller than they could be, and continuous performance has taken a hit with the increased resolution. However, it still compares well on paper and in practice with its rivals, with better specs than Canon and Nikon’s entry-level SLRs and a lower price than their next-tier-up models. It can’t quite match the phenomenal Pentax K-30, which now costs around £500 including VAT. However, if you want an SLR-like camera but also want live view, video autofocus and lots of novel shooting modes, the A58 is an excellent choice.