This promises the quality and lens flexibility of a DSLR but in a much more portable package. It's the same theory behind the Micro Four Thirds standard developed by Panasonic and Olympus, but rather than adopt this existing system, Sony has taken a different route, both physically and in terms of target audience.

Most importantly, the NEX cameras employ larger sensors than the Micro Four Thirds standard – in terms of surface area they're over 50% larger. Indeed the NEX sensors are exactly the same size as those in Sony's range of cropped-frame DSLRs. Rather than recycling an existing sensor though, Sony's developed a new CMOS model for the NEX cameras which offers 14.2 Megapixel resolution and HD movie capabilities. The latter is one of the major differences between the NEX-3 and NEX-5, with the former supporting 720p resolution and the latter boasting 1080i, but the still image quality on both models is identical.

The NEX cameras may share the Alpha branding, but to exploit their shorter lens-to-sensor distance, a new mounting has been developed. The new E-mount supports three lenses at launch: an 18-55mm standard zoom, an 18-200mm super-zoom and a 16mm pancake model. The lens mount may be different from Sony's DSLRs, but by sharing the same sensor size, the field-reduction remains 1.5 times. So the 18-55mm kit lens delivers an equivalent range of 27-83mm and the 16mm pancake works like a 24mm.

Unlike the Alpha DSLRs though, there's no room for stabilisation to be built-into the NEX bodies, so instead Sony's equipped the two zooms with optical stabilisation; there's no stabilisation for the 16mm pancake. Sony also offers an adapter which allows the NEX cameras to use Alpha lenses, but they become manual focus only.

Despite their compact dimensions, Sony's fitted both the NEX-3 and NEX-5 with high resolution screens which vertically tilt for easier composition at high and low angles. They also offer fast continuous shooting options at up to 7fps, so long as you're willing to have the focus and exposure locked at the first frame.

This fast continuous shooting is also exploited in a number of innovative modes first seen on selected Sony Cyber-shot compacts, like the HX5. Like that model, the Handheld Twilight and Anti Motion Blur modes automatically combine six exposures to reduce noise or camera shake respectively. Then there's the HDR mode which automatically combines three different exposures to extend the dynamic range of the image. The NEX cameras also feature Sony's clever Stitch Panorama mode, which automatically generates a wide panoramic image with a single sweep of the camera; NEX cameras updated to firmware version 2 even offer an option which generates a 3D panorama for compatible TVs.

All this is packed into tiny bodies which actually make existing Micro Four Thirds models look relatively large, and adding extra class are metal-bodied kit lenses. What makes the NEX cameras really different to rival cameras which pack large sensors into small bodies though is their target audience and user interface. While Panasonic, Olympus and Samsung all target point-and-shoot owners looking to upgrade, they also acknowledge enthusiasts looking to complement (or even replace) a DSLR with a degree of control and customisation they'd expect.

Not Sony though, which unashamedly aims the first two NEX cameras at those upgrading point-and-shoot cameras. While there is full manual control available, both NEX cameras have minimal buttons and a user interface designed for beginners. Many settings are buried away in various menus, and while this keeps things simple for beginners, it could infuriate more experienced users.

In our full review, we'll take a close look at the innovative features of the NEX cameras, along with the software which drives them. Does the big sensor really deliver DSLR-quality and is the kit zoom a good match for it in practice? Is the movie mode a viable replacement for a conventional camcorder? Do the innovative shooting modes extend the performance of the camera, or are they best-suited to traditional compacts? And as importantly, what's the handling like on such a small body and does the beginner-friendly user interface help or hinder? Read on to find out!

Sony Alpha NEX-3 and NEX-5 differences

The Sony Alpha NEX-3 and NEX-5 are identical apart from the following:

NEX-3 body is made from plastic / NEX-5 body is made from magnesium alloy.
NEX-3 body is fractionally larger with different shaped grip.
NEX-3 best quality video is 720p with MP4 encoding / NEX-5 best quality video is 1080i with AVCHD encoding.
NEX-3 does not have an IR remote option / NEX-5 does have an IR remote option.

Testing notes

We tested a final production Alpha NEX-5 updated to run firmware version 2. The cheaper NEX-3 shares the same sensor, so the image quality seen here is reflective of what's possible with that model. While the review is based on using the NEX-5, we'll illustrate the minor differences between it and its cheaper sibling throughout. We tested the NEX-5 with a final production 18-55mm kit lens. We were also supplied with a pre-production 16mm pancake, but due to widely reported issues with the image quality, only used it for physical evaluation; all results here were taken with the 18-55mm.