Fashionably late: Sony has finally released its alternative to the already popular Olympus EP-2 and Lumix DMC-GF1 micro four-thirds, interchangeable lens cameras. Using the same technology that Olympus and Panasonic pioneered, the Alpha NEX-3 and NEX-5 are effectively compact DSLR cameras, light enough to carry around at all times but still capable of taking high-quality RAW files. Panasonic, which brought out the first micro four-thirds camera in 2008, made the mistake of creating a bulky, conservative-looking camera. Sony, however, has made compactness its priority, emphasizing one of the key benefits of a micro four-thirds system — it's light. Both of the cameras undercut their rivals in the weight stakes. Without batteries, the NEX-5 tips the scales at 229 grams and the NEX-3 is just an extra 10 grams. Panasonic's most recent micro four-thirds, the Lumix DMC-GF1, weighs 285 grams, and the Olympus EP-2 is 335 grams. The two Sony models are also demonstrably smaller, although both the Panasonic and Olympus cameras are slightly thinner.

The NEXs use a 14.2-megapixel Exmor APS-HD CMOS sensor, which packs in more pixels than those in the GF1 and EP-2. Its lens mount, the E series, is compatible with Sony's new range of E lenses, which includes a 16 mm F 2.8, 18-55 mm F3.5-5.6 and an 18-200 mm F3.5-6.3. To use Sony's regular A-mount lenses on these new cameras, however, users will still have to buy an LA-EA1 adapter.

Sony's LCD screen is tiltable, something new to the micro four-thirds, and unlike its rivals, the NEX 5 can record video at full HD resolution of 1,920 x 1,080 pixels (others are limited to 1,280 x 720 pixels). Sony has also heeded complaints about some micro four-thirds' slow shooting rates, with these shooting at up to 7 fps. Though neither NEX comes with an built-in flash, they do include external add-ons.