There are quite a few premium fixed-lens cameras available with F2.0 lenses, manual exposure controls, and sensors that are larger than the ones found in run-of-the-mill compact cameras. However, there has never been a compact camera with a sensor size anywhere close to that of the just-announced Sony Cyber-shot RX1. The RX1 somehow packs a full-frame sensor into a relatively compact, fixed-lens body.
To put that sensor-size-to-body-size ratio in perspective, most consumer-level DSLRs don't have a sensor nearly as big as the one found in the Cyber-shot RX1. Only the biggest and most-expensive DSLR cameras offer full-frame sensors, and professional photographers are usually the only people who buy them.
A full-frame sensor measures 36mm by 24mm, which is about 2.3 times the size of the APS-C-size sensors found in most entry- to mid-level DSLRs. It's about 20 times the size of the 1/1.7-inch-type sensors found in most premium point-and-shoot cameras.
The RX1's 24.3-megapixel full-frame sensor is also about 7.4 times the size of the sensor found in the Sony Cyber-shot RX100. You may remember the Cyber-shot RX100 as the camera the photography world was drooling over when it was announced earlier this year, primarily due to the fact that it had a very big sensor for a pocket camera—a "very big sensor" that's 0.13 times the size of the one tucked in the RX1.
In practical terms, that full-frame sensor should mean the RX1 performs extremely well in low light, especially when you consider its wide-aperture F2.0 lens and its maximum ISO setting of 25,600. That sensor/aperture combo should also capture very shallow depth of field in macro mode.
As you'd expect, the RX1 also comes loaded with all the features found in Sony's higher-end cameras, such as 1080p video recording at 60fps or 24fps, manual exposure controls for both stills and video, RAW shooting, and automated modes for HDR photography and other creative effects. The camera also features a control ring around the lens for adjusting aperture settings, a pop-up flash, and a standard ISO hot shoe for external accessories.
With bigger sensors come bigger body sizes, and the RX1 isn't exactly a "pocket camera," even though it's impressively small for its imaging prowess. At 4.5 inches wide and 3 inches tall, it's closer to the size of beefier cameras such as the Canon PowerShot G12 and Nikon Coolpix P7700 than it is to the size of its Cyber-shot RX100 sibling.
Bigger sensors also translate to bigger prices, as well, and the RX1's asking price puts it firmly in the realm of enthusiast niche cameras. If the $2800 price tag isn't enough to make you flinch, then the fixed focal length of 35mm on the RX1's F2.0 lens might. That means you can't zoom unless you move your feet.
If you're interested, start doing calisthenics and saving up now, because the Cyber-shot RX1 is due in November.