Sony Alpha 33 review

Squeezing into the gap between hybrid and DSLR: The Sony A33

Hybrid models may have sparked something of a revolution in the photography market, but manufacturers have long been tweaking SLR templates for one reason or another.

Sony’s latest single lens translucent (SLT) represents another turning point for camera design, and while the venture retains the idea of using a mirror, the way in which Sony has done so makes the A33 unique. Typically in a DSLR, the mirror divides incoming light between the AF sensor at its base and the viewfinder. On hybrid models, where there is no mirror, all of this light passes through to the sensor, which means that phase-detection AF isn’t possible. Yet on Sony’s new SLT system, the mirror remains and 70% of incoming light passes through to the sensor, while the remaining 30% gets redirected upwards towards an AF sensor. This means that full-time Live View and phase-detection AF are possible at the same time.

With a mirror in place, the A33 resembles a DSLR more than it does a compact or hybrid model, and so it continues the Alpha mount common to all Sony DSLRs. This new construction doesn’t allow for a standard optical viewfinder, though, and in its place there’s an electronic alternative with 100% scene coverage and a resolution of 1.15million dots – just slightly short of the 1.44 million on Panasonic’s G-series models.

The LCD screen, however, is a perfect match for competing models, with a 920k-dot resolution and Sony’s TruBlack technology said to better maintain detail and contrast. It may also be articulated around a central point at its base, which enhances functionality of both Live View and video shooting.

Images and videos are captured on a 14.2MP CMOS sensor, APS-C in size and based on Sony’s Exmor technology. This is the same sensor as that in Sony’s NEX-3 and NEX-5 models, and offers full HD recording in an AVCHD format at 1080i. Surprisingly the camera also offers stereo sound recording as standard, although a microphone input has also been provided for external mics. Other features include Sony’s Sweep Panorama mode, which can record both 2D and 3D panoramas, and a 7fps burst facility which achieves this speed without compromising on resolution.

Sony has generously lined the A33 with rubber around its grip and towards the thumb rest, and the latter has been contoured for better purchase. In the hand the camera is comfortable, and at just over 700g with its kit lens it’s no problem to carry for long periods, while direct buttons for many features are positioned around the body. These include a Movie button just to the side of the thumb rest and Sony’s long-standing Fn button for commonly-used menu options, although the D-Range button on the top plate would perhaps be more useful if assigned to a custom option.

Sony has previously claimed that the long wait for video recording in its Alpha range came from a desire to implement the best technology possible. In contrast to other cameras, which use contrast-detect AF to focus during recording, the phase detection system in the A33 focuses smoothly and without any incremental ‘stepping’. With the kit lens (fitted with Sony’s smooth autofocus motor), there is a little noise as it does this, but this is only noticeable when recording footage with no sounds. Sony has also managed to get the focusing speed to a sweet spot, where it’s fast enough but not so speedy that it brings attention to itself during a recording. Even in poorer lighting conditions the system does well to find focus, too.

There’s less reason for the focusing system to be quite as silent when shooting stills, and with the kit lens the camera does make a little more noise when used more conventionally. Even so, focusing is impressively prompt thanks to the three cross-type sensors and the saturated central portion of the frame, although this concentration makes it harder for any peripheral details to be taken into account. This is in contrast to other systems, which have a wider spread of AF points for this very purpose.

Electronic viewfinders have, historically, ranged from admirable to abominable. The viewfinder on the A33, however, is bright and clear, and it displays a high level of detail. It maintains a stable image as the camera is panned, only struggling at longer focal lengths and in lower light, and adjusts itself quickly to any changes in brightness. As an electronic device, however, it is susceptible to a few undesirable effects, such as noise in low light and minor aliasing effects when shooting anything with fine detail. It also suffers from delay in its refreshing once an image has been taken.   

In terms of image quality, exposures are generally fine and the metering system is largely reliable, though at times the camera seems to overexpose the odd image when faced with darker details. Similarly, the auto white balance system is generally good, although now and again the system turns out slightly warmer or colder results than expected. JPEG processing noticeably reduces some of the worst chromatic aberration which is visible in RAW images, and the moderate amount of sharpening applied enhances definition of fine details. While the increase in contrast in JPEGs is also welcome, a comparison with RAW files shows that a significant proportion of shadow detail is sacrificed because of this. The kit lens shows a little barrel distortion but not enough to cause concern, and maintains very good sharpness to the corners and edges of the frame when sufficiently stopped down.

Noise is fine up until around ISO 800, and detail is still fairly good as high as ISO 6400, although this isn’t evident from the camera’s JPEG images. Here, the boost in contrast masks noise in darker areas, and the noise reduction does a good job of removing the harshest noise, but images are a little soft. The significant drop in quality at the highest sensitivity of ISO 12800, where noise takes on a coloured blotchy appearance, makes this setting tricky for low-light work.

Sony has pitched the A33 at the most appropriate market, and outside of hybrid models it’s perhaps one of the more interesting developments to address the fusion of still and video capture. You do need to take advantage of the latter, though (or even just Live View) to appreciate its intended purpose. This isn’t to say that the A33 isn’t capable of a high standard of image quality – it’s just that not every stills photographer will prefer the combination of an electronic viewfinder and articulated LCD screen.