Expert's Rating
Pros
- Larger sensor and superior lens make for class-leading still image quality and class-leading video performance
- Excellent ergonomics built around clever front control ring and editable Fn menu
- WhiteMagic technology makes LCD clear and easy to view even outdoors
- Multiple aspect-ratios including 3:2 and 1:1
- Full repertoire of Sony in-camera processing options including sweep panorama, Clear Zoom, and numerous creative effects
- Design of lens makes lens cap unnecessary
Cons
- None significant
As casual photographers turn increasingly to their smartphones to take pictures, serious shooters who want an ultraportable camera have an exciting new choice in Sony’s DSC-RX100 ($650, as of November 26, 2012). Sony put a larger sensor and a better processor into a smaller body and created a camera that exceeded my expectations in almost every way. 
Bigger is better
The sensor in the RX100 is a 1-inch (13.2mm by 8mm) Exmor CMOS sensor with an effective picture resolution of 20.2 megapixels—darned impressive for a compact camera. You’ll be able to make big prints of images captured at that resolution, and even if you don’t print, you’ll have lots of detail to crop, sharpen, and enhance.
Equally important is the size of the sensor. A larger sensor means better light-gathering ability. The RX100‘s sensor packs twice as many photosites (individual light-sensing points) as the sensors in the Panasonic Lumix DMC-LX5 and the Lumix DMC-LX7, and it fits them into a space that’s almost three times as large. The Panasonics are strongest at ISO 400 or below. The Sony RX100 continues to perform well at higher ISOs and captures greater dynamic range at any ISO. 
Small is beautiful
Despite its much larger sensor, the RX100 weighs less than the Panasonic LX5 or LX7 and is actually smaller and easier to fit into your pocket.
Sony’s engineering achievement required some compromises as well as some new ideas. You don’t get a flash hot shoe or a viewfinder. The mode dial and shutter button are recessed into the top of the body, as are the brackets that the camera’s carrying strap ties through. One minor complaint I have about the RX100 is that it lacks any sort of molded grip, and its sleek rounded design makes me worry about dropping it. (An inexpensive, well-made third-party product—Richard Franiec’s $35 Sony RX100 Custom Grip—resolves this problem without making the RX100 bulkier.)
Perhaps the most remarkable aspect of the RX100’s design is how fully the lens collapses into the camera’s body. When the LX5 is turned off, its lens with protective lens cap juts out twice as far as the RX100’s lens does when that camera is turned off. (Instead of using a lens cap, the Sony model relies on an interlocking blade design.) Yet when the cameras are turned on, the RX100’s lens extends farther.
Lens and LCD
To take a great digital photo, you need more than a great sensor. The RX100 is blessed with a Carl Zeiss Vario-Sonnar T* lens with a 35mm-equivalent focal length range of 28–100mm or roughly 18–65 in APS-C terms. Fully extended, the lens’s aperture is f/4.9, which isn’t bad; and at its widest, the lens has a maximum aperture of f/1.8, which is amazing. Best of all, even at f/1.8 the lens performs flawlessly.
The rear LCD uses Sony’s RGBW WhiteMagic technology to provide a bright and very clear view even when you work in bright sunlight.
Image quality
Many cameras sold today get Good or Very Good ratings when tested in the lab. Digital technology is maturing. But even in this highly competitive environment, the RX100 stands out. TechHive Labs gave the Sony Cyber-shot RX100 the highest marks across the board: Exposure was Very Good, color was Superior, sharpness was Perfect, distortion level was Superior, video was Perfect, and video sound was Very Good. The camera earned an overall performance mark of 92—the highest for any recent compact, fixed-lens camera.
In my hands-on use, the camera’s output supports these ratings. Whether shooting Raw or JPEG images, I’ve often obtained better results from the RX100 than I ever got from other compact cameras in clarity, sharpness, and tonality. When I’ve challenged the RX100 with too much light, or too little light, it has responded with accurate exposure, excellent exposure range (dynamic range), and—in low light—less noise than I thought possible from a camera this small. In many cases, the RX100’s images invite comparison with images produced by much more expensive tools, such as my Sony Alpha SLT-A77.
A compact for control freaks
The RX100 can be a point and shoot, if you stick with an automatic modes such as Auto, Auto+, or P (Program). But Sony calls the RX100 a “professional compact camera,” and this is a camera for photographers who want to be in control.
The RX100 offers a wide range of control modes, including PASM (program, aperture priority, shutter priority, and manual) modes, Sony’s outstanding sweep panorama mode, and movie mode. The menus will be familiar to users of Sony’s recent digital SLT cameras. You can set the upper and lower limits for Auto ISO, a feature normally found only on intermediate or higher-level interchangeable lens cameras.
You can use the control wheel surrounding the RX100’s lens to do a number of things, such as selecting options in the Fn menu, changing the aperture in A or M modes, and controlling the superb Program Shift feature in P. Indeed, Program Shift works so well on the RX100, thanks to the control wheel, that I shoot almost exclusively in P, unless I need to switch to M. The control wheel also lets you focus manually and here it can be helped, if you wish, by two other nifty features: focus peaking, and focus magnification.
Another of my favorite RX100 features is the editable Fn menu. At the press of a button, I have access to the seven settings that I consider most important—without having to rummage through others that I care less about. I wish I could do this on my A77!
Perfect video
If you’re looking for a movie camera that you can put in your pocket, look no further. TechHive’s lab analysts and jury gave the RX100’s video output a score of Perfect.
The RX100 supports a range of video formats and resolutions unprecedented in a compact camera, including 1920-by-1080 60p PS and 1920-by-1080i 24p FX. It also supports stereo audio input. If you don’t want to use a tripod, you can rely on Sony’s SteadyShot image stabilization, which offers normal and active modes. Since I’m an unregenerate still shooter, my favorite video feature on the RX100 is the ability to take a still shot while capturing video. 
Creative features
Sony continues to pack more in-camera processing options into its cameras than anybody else does. In addition to offering 3:2, 4:3, 16:9, and 1:1 aspect-ratio options, the RX100 complements useful effects ike sweep panorama, multiframe noise reduction, Auto HDR, Clear Zoom and Auto Portrait Framing with such fun or creative effects as Toy Camera, Retro, High Contrast Mono, and Watercolor. 
The bottom line
Just about every shortcoming I can identify in the Cyber-shot RX100 (say, its lack of a hot shoe or GPS) can be explained by Sony’s determination to keep the camera truly compact. My most serious complaint—that the RX100 can’t entirely replace my A77—is the best example of this. Though the A77 benefits from having a larger APS-C sensor and interchangeable lenses, I can use the RX100 in almost every way that I use the A77—for example, to achieve careful manual focus or full manual exposure.
Still, I have to admit that taking full control of the RX100 involves a degree of fussiness that isn’t there when I use the larger camera. This inevitable state of affairs is not a knock against the RX100, however. What makes the RX100 so special is its combination of outstanding image quality in a pocket-size, go-anywhere device with ergonomics that make taking control of the camera easy and enjoyable.
For more information, see the TechHive Test Center’s normal videos, low-light videos, and test stills.
Photos by William Porter. All rights reserved.