Tested: Sony Cyber-shot DSC-RX100 Compact Camera

Over the Past few years, we have seen a parade of compact cameras with what we have been calling large sensors. But “large” is relative, and what’s more important than physical size is what you do with that surface area.

The newly developed 1-inch sensor in Sony’s pocket-sized Cyber-shot DSC-RX100 ($648, street) measures precisely 13.2x8.8mm. To put this in perspective, it has about 2.7 times the surface area of the 1/1.7-inch sensor in Canon’s slim PowerShot S100. Confused? Sensor nomenclature is tricky: The designations “1-inch” and “1/1.7-inch” correlate to the vacuum tubes once used in video cameras long ago.

That is, indeed, large for a compact. However, you’d have to multiply the surface area of the RX100’s sensor by about 1.9 to match the sensor in a Micro Four Thirds body, or by 2.4 to catch up to the sensor in Canon’s larger-bodied PowerShot G1 X, or by 2.8 to get to the APS-C sensors in Sigma’s DP Merrill line of pocket compacts. And, of course, a full-frame sensor dwarfs this Sony’s, with 7.4 times the surface area.

Still, Sony packed 20.2 mega-pixels into its 1-incher. To deliver plenty of light to it, the camera sports a Carl Zeiss-branded zoom lens with a relatively fast maximum aperture range, f/1.8–4.9, and coverage equivalent to a 28–100mm full-frame lens.

A control ring around the barrel of the pancake lens works in tandem with the click-wheel on the back, lending a traditional feel to shooting in manual mode. It also provides flexibility in controlling other camera settings when shooting in other modes.

Does all this pay off? Read on.

In the Test Lab
The RX100’s imaging ends up close to what you’d expect from an advanced compact. It managed to score an Extremely High rating in overall image quality at its lowest sensitivity of ISO 80. But for the majority of its sensitivity scale, it ends up with a Very High rating as resolution fell below our cutoff of 2250 lines. At ISO 400, resolution had dropped to 2170 lines; at its worst, at ISO 6400, it turned in 1930.

This places the Sony ahead of Canon’s 12.1MP S100 slim compact, which resolved 2100 lines at ISO 80 and fell to 1300 lines at ISO 6400. But it also made us wonder why Sony didn’t opt to keep the pixel count lower—say 16MP—to keep noise down.

Indeed, the RX100 produces noisier images at ISO 80 than the S100 does at ISO 400, and the Sony held noise to Low or better ratings only up to ISO 200. By ISO 800, noise was high enough to earn an Unacceptable rating and remained so up to the camera’s top sensitivity of ISO 6400.

Some context: Noise becomes less noticable as image size decreases. For example, the candid portrait shown in the LCD to the right was shot at ISO 800. In a print this small, you’ll have to strain to see the noise. But it’s there, and in a bigger print, the noise would become distracting.

In our color accuracy test, the RX100 easily earned an Excellent score. It turned in an average Delta E of 6.6,­ well below our cutoff of 8 for top honors in this lower-is-better test.

In the Field
The RX100’s body has a solid feel and compares well with cameras in this class. We wish it had some sort of grip, but we also know that the designers probably felt that any protrusion on the front would take away from the body’s clean, attractive look. We tend to let practicality trump style, but also recognize that people looking for a compact camera like this might not.

The controls benefit from the ring around the lens. In manual or aperture-priority mode, this sets aperture for a classic feel, albeit without click-stops. Press the function button on the back, and the ring can now be used to adjust several settings that you can customize in the menus.