Sony Alpha SLT-A37 review

Looks can be deceiving. The Alpha SLT-A37 isn't technically a dSLR -- it's what Sony terms an SLT (single-lens translucent), the 'translucent' applying to the mirror that sits in front of the sensor.

It has much in common with a compact system camera like Panasonic's Micro Four Thirds range in that it has no optical viewfinder, yet it boasts the benefits of a dSLR, including a choice of interchangeable lenses.

You can pick up the Sony Alpha SLT-A37 for around £400 for the body only.

Specs

The lack of an optical viewfinder shouldn't be a cause for concern, as the screen in its eyepiece is fine-grained and very detailed. Image quality on it is excellent. The overlaid graphics showing shooting settings, focus points and so on, are finely rendered and extremely easy to read. There's a diopter wheel to one side if you find it's not quite focused for your eyesight, and a proximity sensor just below the eyepiece that switches automatically between that and the 2.7-inch LCD screen on the back.

The screen is articulated through 180 degrees on the horizontal plane, allowing you to tilt it up and down for overhead or low-down shots -- a boon at concerts and sporting events.

There's no optical viewfinder, but its digital replacement is fine-grained and clear, and the LCD display swivels for overhead shots.

The model on test is the A37K -- the K marking out the fact that it's bundled with Sony's 18-55mm kit lens. In 35mm terms, those measurements, which are common to many manufacturers' entry-level kit lenses, equate to 27-82.5mm and represent slightly better than a 3x zoom. Maximum aperture at wide angle is f/3.5. At full telephoto it's f/5.6. Both of these are par for the course.

The sensor is an APS-C-sized chip with an effective resolution of 16.1 megapixels, outputting 4,912x3,264 pixels in JPEG or raw format (or both side by side should you choose). Images are written to either SD or Memory Card, with the two formats sharing a single slot. You can't install them both at once, so it's not possible to split the image formats between different media as you can with the Nikon D800, for example.

The colours produced by the 16-megapixel sensor are bold and realistic, and the kit lens is sharp and accurate (click image to enlarge).

Using the A37

Using a Class 4 memory card in my tests, burst mode shot four full-resolution shots raw files with accompanying JPEGs before needing to pause to clear the buffer. It shot five when saving just raw files, and six when snapping JPEGs, after which it carried on shooting with a delay of around 1 second between each frame.

The A37's maximum sensitivity is ISO 16,000 and the lowest is ISO 100. Low-light performance was very good. At ISO 3,200, there was naturally some noise in the results, but this was kept to a minimum and was sufficiently controlled to not impact the shot greatly. Colours remained true, and when viewed full screen, rather than zoomed to 100 per cent, detail remained sharp.

In low light the A37 kept noise to a minimum. This image was shot without flash or artificial light at ISO 3,200 (click image to enlarge).

It achieve an excellent result in the still-life test. This involves shooting a collection of everyday objects under studio lighting, and again using both the available ambient light and the camera's onboard flash.

Under studio lighting, and with the aperture set to f/13 to extend the depth of field, the A37 set its sensitivity to ISO 500, but the level of the noise in the image remained very low. Fine detail was cleanly rendered and barely disturbed by the additional grain.

It resorted to ISO 3,200 when shooting in ambient light. Although some of the white background lost detail, other bright objects, such as the white fur on a child's toy, were full of texture and demonstrated no clipped highlights. The noise seen in the previous ISO 3,200 test was also evident here, and it made it impossible to read very fine writing on the label of a miniature spirit bottle. Otherwise, the frame was cleanly and accurately rendered.

When using the flash, there was a rather sharp and slightly unattractive fall-off in the level of illumination towards the back of the scene, and a shadow from the lens barrel at the bottom of the frame. Furthermore, the shadows that it cast were slightly harsh -- particularly when compared with those cast by the consumer Sony Cyber-shot DSC-W690. However, noise was greatly reduced, despite sensitivity still being set to ISO 800. Small characters on my test objects were easy to make out.

The Sony Alpha A37's high-sensitivity, low-light performance helped it handle the still-life test well (click image to enlarge).

How well the camera copes with straight lines across the frame can only be judged in relation to the kit lens supplied, but in my tests it was excellent. The horizontal and vertical lines in the test grid run parallel, as they should, and display no evidence of barrel (bloated) or pin-cushion (pinched) distortion.

The lens geometry test produced no evidence of barrel or pin-cushion distortion in this grid shot.

Macro performance

The kit lens' minimum focusing distance is a fairly chunky 25cm, yet macro performance is good. Standing back and zooming to around halfway through the lens' range produces a beautiful shallow depth of field, with rapid fall-off in the focal zone and plenty of detail in the sweet spot. The focused subject is sharp and satisfying, and again, colours are accurate and true to the originals.

The A37 has very effectively isolated the subject, with a rapid and attractive fall-off in the level of focus surrounding it (click image to enlarge).

Stills tests

In more conventional settings, the A37 is hard to fault. It did an excellent job of extracting the maximum colour information from any scene throughout my tests, with particularly expressive skies on an otherwise overcast day.

In the church spire shot below, the tones in the sky are impressive, with a wide variety of blues and whites producing deep, satisfying texture. Despite this, it hasn't thrown the comparatively shaded face of the background tower into darkness.

There's plenty of texture in this sky, helping to produce an interesting background for an otherwise conventional shot (click image to enlarge).

This ability to balance tones was a constant, even in more demanding set-ups. The A37 retained significant colour data even in areas that initially appeared to be lost to the shadows.

I set it to capture raw files alongside JPEGs throughout my tests, and on downloading the results, it was easy to recover a lot of hidden detail from shadow areas in the raw data. As can be seen in the animation below, the archway appears black, caused by the camera correctly exposing for the lighter background, but the image contained sufficient detail to recover the colour and texture of the wooden arch in post-production.

What looks like an area lost to the shadows is actually packed with detail that can be brought back into view in post-production.

It was easy to isolate subjects in all shooting scenarios. Even when focusing tightly on a particular part of the scene, the A37 accurately and consistently exposed the rest of the frame.

In the shot below, the point of focus is a very shallow area on the gravestone, yet the surrounding ground, buildings in the background and, in particular, the sky, show enormous variation and texture, without any evidence of clipped highlights or lost shadow.

Even those areas that lie outside of the point of focus are accurately exposed (click image to enlarge).

Video test

The A37 shoots high-definition video at 1,920x1,080i resolution, 50 frames per second in AVCHD format. Results were excellent. The clean soundtrack is a particular highlight. It cleanly recorded faint, distant sounds like rain, without them becoming overwhelmed by more prominent noises, like passing cars.

It compensates smoothly for extreme changes in light levels -- there was no stepping.

There isn't a powered zoom as the kit lens is fully manual, just like a regular dSLR, so you'll need a steady hand if you want to achieve a smooth zoom while filming. The lens supplied with my review camera was a little stiff so the results were jerky. It's not possible to say whether or not it would loosen up over time, but it could be that it just needs wearing in.

Overall though, the video results were among the best I have seen from a high-end consumer camera, making the A37 a great choice not only for stills, but for movies too.

Conclusion

If you haven't gleaned this already, the A37 is an excellent camera. In the A37K package, the body has been paired with a high-quality, sharp all-round lens, and it's extremely well priced.

If you shop around, you should be able to pick one up for around £430, both from mainstream e-tailers like Amazon, and on the high street. You can't deny that's tempting.

If you want to weigh up some more options before buying, check out my round-up of the best interchangeable lens cameras, including the outstanding Panasonic Lumix DMC-GF5.