Sony RX1 Technical Info

by Mike Tomkins

The story of the Sony Cyber-shot RX1 is one that begins and ends with its Exmor-branded, 35mm full-frame CMOS image sensor, said to have 2.4x wider dynamic range than that in the Sony Alpha DSLR-A900 from just four years ago.

It's the first compact camera to feature a full 35mm frame-sized image sensor, shown at left in the picture above. The difference in size is massive, even when compared to the typical APS-C sized sensor (center) found in most SLRs and mirrorless cameras--a sensor most photographers think of as being large. At right is an example of the 1/2.3-inch sensor found in several premium compact cameras. By comparison, it looks much like a postage stamp, with a vastly smaller area available to gather light.

The Sony RX1's image sensor has an effective resolution of 24.3 megapixels, and a total resolution of 24.7 megapixels.

Sensitivity ranges from ISO 100 to 25,600 equivalents, and can be expanded at the bottom end of the range to as low as ISO 50 equivalent. A Multi-Frame NR function can extend this to ISO 102,400 equivalent at the upper end of the range.

For movies, there's a narrower sensitivity range of ISO 100 to 6,400 equivalents.

The full-frame imager is coupled with a Sony BIONZ image processor which allows full-resolution burst shooting at a rather sedate 2.5 frames per second in standard continuous mode.

A Speed Priority Continuous mode raises this to five frames per second.

The other truly dominant feature of the Sony RX1 is its lens. With a full-frame sensor, the Carl Zeiss Sonnar T*-branded optics must provide for a much larger image circle than any other compact camera. As the sizeable element above shows, doing so requires a not-insignificant amount of glass!

Sadly, a zoom lens was simply out of the question while retaining any measure of pocketability, and so the RX1 instead features a 35mm prime lens with an f/2 maximum aperture. The minimum aperture is f/22, and there's a physical aperture dial.

The RX1's lens design includes eight elements in seven groups, of which three are aspherics. One of these, says Sony, is an Advanced Aspherical element, a technology introduced in the HX20, WX100, and W690 earlier this year.

There's a nine-bladed aperture for pleasing bokeh in out of focus areas, and a T* coating to reduce ghosting and flare.

The lens barrel is equipped with a 49mm thread for screw on filters.

Ordinarily, the minimum focusing distance is 9.5 inches (24cm). In Macro mode, this falls to 5.5 inches (14cm) from the front lens element. The maximum magnification is 0.26x.

Camera shake-induced blur is somewhat less of an issue, given the RX1's large sensor area, bright lens, and relatively wide-angle view.

Still, it's a bit of a shame that the RX1 lacks any form of mechanical image stabilization.

There is an electronic stabilization function, but it applies only for movie capture and induces a focal length crop of almost 1.2x for 16:9 video.

At first glance, the RX1's image sensor seems to be the same as that in the Alpha A99 digital SLR: resolution, size, and sensitivity range are all the same.

Where that camera has on-chip phase detection AF, though, the RX1 relies solely on contrast detection. Sony says the RX1's sensor is a variant with no PDAF points.

The contrast detection system has 25 autofocus points, selected automatically or manually. Multi, Center and Flexible Spot area modes are available.

Focus modes available are: Autofocus (AF), Manual Focus (MF) and Direct Manual Focus (DMF). The latter lets you focus manually, with an AF operation to get you in the ballpark.

Note that Continuous AF mode for stills has been dropped on production units, so the separate "S" and "C" settings seen on some prototype units no longer exist, replaced by the single "AF" setting which enables Single-shot AF in still mode and Continuous AF in movie mode.

The Sony RX1 excludes a built-in viewfinder, in favor of a smaller body size. However, Sony is offering two viewfinder accessories paired to the RX1.

A shoe-mounted optical viewfinder, shown above, is one option. The other is an XGA OLED Tru-Finder electronic viewfinder that mates to contacts in the front of the new Multi Interface Shoe.

There's also a three-inch LCD panel with VGA (640 x 480 pixel) resolution.

Sounds pretty standard, until you look at the dot count. It's a Sony WhiteMagic display with four dots per pixel, for a total of 1,228,800 dots. As well as red, green, and blue dots, there are white dots that are used to boost brightness outdoors, and reduce power consumption indoors.

A built-in auto popup flash strobe is included, with a guide number of six meters (ISO 100).

With Auto ISO, range is rated as 0.75 to 21.7 meters. Boosting the sensitivity to ISO 25,600 raises this to as high as 43.4 meters.

Flash modes include Auto, Fill-flash, Slow sync, Rear sync, Off, and Wireless.

Maximum sync speed is 1/4000s, thanks to the RX1's leaf shutter.

There's also a new Multi Interface Shoe, in place of Sony's usual proprietary shoe. Intelligent contacts sit at the front, and the new shoe is also compatible with ISO 518 dumb strobes.

As well as flash strobes, the Multi Interface Shoe supports accessories.

We've already mentioned the optional electronic and optical viewfinders; Sony says other choices will include clip-on LCD monitors and thumb grips.

The Sony RX1 includes the usual array of exposure modes that you'd find on an interchangeable-lens camera--Auto, Program, Aperture- and Shutter-priority, and Manual--plus three handy User modes that save settings for later recall. There's also a consumer-friendly Scene position, a dedicated Movie mode, and a Panorama mode.

The Program mode includes a program shift function that lets you bias exposure in your chosen direction, while still leaving all variables under automatic control.

Metering modes are also much as you'd expect. There's a selection of Multi-Segment, Center-weighted, and Spot options, all metered with the main image sensor. Sony hasn't yet disclosed how many zones the Multi-segment metering system uses.

Exposure compensation is handled with a photographer-friendly physical dial on the top of the camera. A useful range of +/- 3.0 EV of exposure compensation is available, set with a fixed step size of approximately 1/3 EV.

The Sony RX1 offers shutter speeds ranging from 1/4,000 to 30 seconds, though since it uses a leaf (diaphragm) shutter, that top speed is only available at apertures of f/5.6 or smaller. Maximum shutter speed drops to 1/3,200 at f/4 and 1/2,000 at f/2. In Manual mode, there's also a Bulb position for manual control of shutter duration. Maximum exposure time is 50 minutes plus, apparently limited only by battery life.

White balance modes include Auto, nine presets including Flash and four fluorescent options, custom, direct color temperature input, and color filter.

Sony includes its Multi-Frame Noise Reduction function in the RX1. This is similar to the Handheld Twilight scene mode, but allows direct control of sensitivity.

By combining multiple shots in-camera, a much greater sensitivity limit of ISO 102,400 equivalent is unlocked.

Although there's not an optical zoom lens, Sony's 2x Clear Image Zoom is available. This is a variant of digital zoom that tries to improve quality by using pattern matching. It's still interpolating (read: guessing) the missing data, but it's doing so in a more intelligent manner that Sony has claimed to be "nearly equivalent" to optical zoom. Standard digital zoom is also available up to 4x.

'Clear Image Zoom' is based on Sony's rather clumsily-named 'By Pixel Super Resolution' algorithms, as is the Auto Portrait Framing function. When enabled, this saves two copies of each image you capture. The first is untouched; the second uses face detection to locate your subject, crops the image based on a rule-of-thirds algorithm for what the camera feels to be a more pleasing layout, and resamples the result back up to the same resolution as the original shot, thereby making it seem as if the camera has simply gone back in time and retaken the image with different framing.

Of course, the other creative functions found on recent Sony models are all present: Picture Effects, High Dynamic Range and Dynamic Range Optimizer, Sweep Panorama, and a digital level gauge.

The Sony RX1 can capture 1080p AVCHD version 2.0 video at rates of 60p/i, 50p/i, 25p, or 24p. There's also HDV (Anamorphic HD) and VGA capture in MPEG-4 AVC at a rate of 30p, but strangely, no 720p mode.

Otherwise, though, the video feature set is very rich by fixed-lens camera standards.

Manual exposure control is available, and there's electronic SteadyShot image stabilization. As well as an onboard stereo microphone--the two ports on either side of the flash shoe--there's also external stereo microphone connectivity (3.5mm jack). Even more impressively for a fixed-lens camera, you can mount an external LCD panel in the accessory shoe.

As well as the accessory shoe and stereo microphone jack we've already mentioned, the RX1 includes a Micro USB 2.0 port with recharging capability, and a Micro (Type-D) HDMI high-definition video port with support for "BRAVIA" Sync Consumer Electronics Control (CEC).

Images are saved as JPEG or 14-bit raw files. The Sony RX1 stores data on SD, SDHC, or SDXC cards, or Sony's own Duo, Pro Duo, or Pro HG Duo types.

Power comes courtesy of the same NP-BX1 lithium ion rechargeable battery used in the Sony RX100. Where Sony rated that camera as good for 330 shots on a charge, the RX1 manages 220 shots to CIPA testing standards. If you change the LCD Quality setting from High to Standard to reduce its power consumption, the RX1's battery life increases to 270 shots. That's pretty impressive, given the much larger sensor, albeit there's no zoom motor to drive between shots.

The Sony Cyber-shot DSC-RX1 began shipping in the U.S. market from December 2012. Pricing is set at around US$2,800 for the camera with battery, AC adapter, Micro USB cable, shoulder strap, lens cap, shoe cap, cleaning cloth, instruction manual, and PlayMemories Home software.

List pricing for additional NP-BX1 batteries is set at US$50. A dedicated battery charger (the RX1 does not ship with one) is available for US$50, or you can buy a kit with charger and a spare battery for US$70. The optical viewfinder accessory costs US$600, while the electronic viewfinder is US$450. The thumb grip is priced at US$250, a lens hood at US$180, and a jacket case at US$250.


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