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We've covered the main features of Ricoh's GXR camera system in a separate review because it forms the basis for an entirely new system that accepts interchangeable sensor-plus-lens modules. In this review we will focus on the GR Lens A12 50mm f/2.5 Macro camera unit, which is based around a 23.6 x 15.7 mm CMOS sensor with an effective resolution of 12.3 megapixels. The other camera unit, the Ricoh Lens S10 24-72mm f/2.5-4.4 VC camera unit will be reviewed separately.

The GR prime lens in the A12 camera unit has an actual focal length of 33mm, which is equivalent to 50mm in 35mm format. Its optical design comprises nine elements (one of them aspherical) in eight groups and it spans an aperture range of f/2.5-f/22.

The GR Lens A12 camera unit, which includes an APS-C sized CMOS sensor and 33mm prime lens with macro focusing. (Source: Ricoh.)

Although designated a ‘macro' lens, the A12 lens only focuses down to 7 cm (which is roughly half life size), whereas the S10 lens can focus as close as 1 cm in macro mode.  However, its focal length is ideal for portraiture and the small size and inconspicuous nature of the camera/lens make it ideal for candid and street photography.

The GXR body with the A12 camera unit fitted. (Source: Ricoh.)

The GR A12 camera unit gives Ricoh a direct competitor to the Micro Four Thirds System cameras released by Olympus and Panasonic. The table below compares key features of the GXR with the A12 lens with the Olympus Pen E-P2 and Panasonic GF1 interchangeable-lens cameras (which have slightly smaller sensors) and their main prime lenses.

Design and Ergonomics
Because the A12 camera unit has been designed to complement the GXR body, it is made from the same die-cast magnesium with a black textured cladding on those parts that are exposed when it's attached to the main body. Areas covered when the camera unit is attached are smooth, matte black metal, except for the stainless steel mounting plates.

The camera unit is supplied with a soft rubber cap covering the connector plate, which links the unit with the main body. A whole lot of pins are located within the connector and care must be taken not to allow anything to get into the connector when changing camera units.

The lens protrudes approximately 50 mm from the camera body (52 mm when the lens cap is fitted). It has a barrel diameter of just over 50 mm and a front element that is approximately 20 mm across. A manual focusing ring is located near the front of the barrel. It's about 10 mm wide and has a ridged rubber coating. Aperture settings are controlled by the camera.

Each camera unit is supplied with a soft nylon carry bag with a drawstring closure. The A12 unit also comes with a 36-page, 105 x 75 mm Instruction Manual with very small print. The manual isn't particularly helpful, providing little more than an expansion of the unit's specifications and a graph showing the exposure ranges for different ISO settings with different aperture/shutter speed combinations.

Sensor and Image Processing
The 23.6 x 15.7 mm CMOS sensor in the A12 camera unit has an effective resolution of 12.3 megapixels. This unit also includes the same GR Engine III image processor as the GR Digital III. In most respects, this camera unit should be able to match the quality provided by the leading entry-level DSLR cameras.
Because the image size settings and file formats are controlled by the main camera body's electronics, the A12 camera unit offers the same suite of aspect ratios and range of image sizes as the S10 camera unit. It also supports both JPEG and DNG.RAW file recording.

Unlike the S10's sensor, which has a 4:3 aspect ratio, the A12's sensor is the same as a typical APS-C DSLR and has a 3:2 aspect ratio where maximum resolution is found. Consequently, 4:3 and 1:1 shots are obtained by cropping the sides of the image, while 16:9 shots crop top and bottom. Typical image sizes are shown in the table below.

Unlike the S10 camera unit, the A12 camera unit can support high-definition video recording, although at 1280 x 720 pixel resolution, rather than Full HD (1920 x 1080 pixels). A frame rate of 24 frames/second applies to the three movie capture resolutions, which also include VGA and QVGA. Movie clips may be up to 90 minutes in length - or 4GB in size. The table below shows typical recording times for a 4GB card.

Controls
We've already covered the control interface in our overview of the GXR system so, in this report we'll concentrate on the functions that are specific to the A12 camera unit. These include functions related to the lens, including focusing, aperture settings and digital zoom. Shutter speeds, sensitivity, white balance and flash parameters are also camera unit specific, along with continuous shooting frame rates and buffer capacities.

The lens covers a wider aperture range than the S10 camera unit, extending from f/2.5 to f/22, with a built in neutral density filter provided to enable f/22 to be set in the auto shooting mode. Its normal focusing range is from roughly 30 cm to infinity but pressing the Macro button enables focusing as close as 7 cm, with half life-size reproduction. The lens is threaded to accept 40.5mm diameter filters.

For shooting still pictures, up to 4x digital zoom is available with interpolation up to the pre-set image size or 5.9x digital zoom at VGA resolution. Only 3.6x digital zoom is available in movie mode.

Focusing is contrast-based. Focus modes are the standard offerings selectable via the main menu and include Multi and Spot AF, manual focus, Snap (selectable in 50 cm increments from one to five metres plus infinity) and infinity. The Snap mode is handy for night shots (where the review camera found focusing difficult) and snapshots where autofocus lag could cause you to miss shots. Focus lock is the standard half-press of the shutter button and an AF-assist lamp is provided for shooting in low light levels.

ISO sensitivity starts at 200 (instead of 100, as in the S10 camera unit) and extends to 3200. Like the S10 camera unit, the A12 camera unit has an Auto Hi setting that enables users to limit the maximum sensitivity in the auto mode, providing a choice of ISO 200, 400, 800, 1600 or 3200.

Higher shutter speeds are supported in the A12 camera unit, which goes up to 1/3200 second, where the S10 camera unit tops out at 1/2000 second. Both cameras support long exposure times up to 180 seconds, allowing images to be recorded in near-total darkness. Such long exposure times can be used for capturing star trails and the trails left by aircraft as they move across the night sky. They can also be used to blur moving water in low-light conditions. (A tripod is vital in such situations.)

Performance
Not unexpectedly, the stand-out feature of the A12 camera unit is its high ISO performance - particularly with long exposures. In our test shots, noise levels at ISO 3200 with 100% magnification were similar to most compact digicams at ISO 400. Noise was certainly visible but it was very well controlled and we could see no loss of detail in subjects.

The dynamic range in shots was also wider than we found with the S10 camera unit, with highlight detail recorded in subjects photographed in bright, midday sunlight. Shadow clipping was also less common than we found with the S10 camera unit. Colours were nicely rendered with the default Image Setting (Standard). Snapshooters may prefer the Vivid setting, which produces a similar colour intensity to many popular digicams.

Imatest confirmed out subjective assessments and also showed the review camera to meet expectations for a 12-megapixel camera with both JPEG and raw files. However, edge softening was detected, particularly at wide apertures. The graph below shows the results of our tests.

Differences between JPEG and DNG.RAW file images remained quite low with high ISO settings, thanks to the light-gathering ability of the larger photosites. However, Imatest showed a slight decline in resolution as sensitivity was increased, as shown in the graph below.

Image noise remained negligible in long exposures right up to ISO 3200, where shots showed the degree of granularity we normally associate with ISO 200-400 shots from small-sensor digicams. The same was true of flash exposures at high ISO settings. Shots would be printable at A4 size - and probably a little larger.

Auto white balance performance was similar to most cameras we've reviewed. Shots taken under incandescent lighting retained warm cast, while shots taken with fluorescent lighting were close to colour cast-free. For both lighting types, the pre-sets slightly over-correct colours but the manual measurement system delivered a neutral colour balance with both types of lighting.

Video quality was in line with other 720p-capable cameras we've reviewed, although the sound recordings with clips were unexceptional. The high-resolution LCD monitor made composing scenes easy but the lack of stabilisation in the lens system meant clips coudl become jerky at times.

The A12 camera unit was slightly faster to power-up than the S10 camera unit, taking just over two seconds before the camera was ready to shoot. For some strange reason, the lens barrel extends out and then in again, even though optical zooming isn't supported. This, naturally, is partly responsible for the delay.

Autofocusing lag was also an issue with the A12 camera unit, although it wasn't quite as serious as we found with the S10 camera unit. We measured an average capture lag of 1.4 seconds, which was reduced to just under 0.1 seconds with pre-focusing. Still not fast enough for a camera at this price point.

Shot-to-shot times were similar to the S10 camera unit, averaging 2.4 seconds without flash and 4.5 seconds with. JPEG Ff files were processed in less than one second, while DNG.RAW files took between one and two seconds, depending on the size of the paired JPEG file.

Continuous shooting speeds were the same as for the S10, although processing times were slightly longer because the image files are larger. A burst of 10 high-resolution JPEGs was recorded in 2.7 seconds, which equates to just under four frames/second. It took 4.5 seconds to process this burst.

Shooting DNG.RAW files with JPEGs reduced the number of files in a burst to four, regardless of the size of the JPEG file. Four Raw+Large/Fine JPEGs were recorded in 1.2 seconds and took 9.8 seconds to process, while four Raw+VGA JPEG files were processed in7.7 seconds.

The M-Cont Plus mode records shots at a rapid rate while the shutter button is being pressed. can record a burst of low-resolution JPEGs  In this mode, the review camera was able to capture 20 3M-sized JPEGs in 2.1 seconds. It took 9.1 seconds to convert this burst into an MPO file.

Buy this camera if:
- You want a well-built, inconspicuous camera for street and candid photography.
- You want a small camera with raw file support.
- You'd like the ability to shoot both still pictures and HD video clips with the same camera.
- You enjoy taking pictures in low-light conditions.
- You're interested in investing in extra camera units as the system evolves.

Don't buy this camera if:
- You're looking for a low-priced point-and-shoot digicam.
- You require fast autofocusing, fast continuous shooting speeds and a large buffer memory for high-resolution images.

IMATEST GRAPHS
JPEG images

Raw images converted with Adobe Camera Raw.

SAMPLE IMAGES

Auto white balance with incandescent lighting.

 
Auto white balance with fluorescent lighting.

 
Dynamic range example; 33mm focal length, ISO 200, 1/60 second at f/5.6.

Macro setting; 33mm focal length, ISO 200, 1/870 second at f/8.9.

33mm focal length, ISO 200, 1/1000 second at f/8.

100% crop from the above image showing the absence of coloured fringing.

30-second exposure at night at ISO 200, f/4.

30-second exposure at night at ISO 800, f/7.1.

15-second exposure at night at ISO 3200, f/8.

100% crop from the above image showing the retention of detail, despite noise-related granularity.

Flash exposure at ISO 200; 1/50 second at f/2.5.

Flash exposure at ISO800; 1/50 second at f/2.5.

Flash exposure at ISO3200; 1/60 second at f/2.5.

33mm focal length, ISO 200, 1/800 second at f/8.

33mm focal length, ISO 200, 1/30 second at f/4.5.

33mm focal length, ISO 200, 1/640 second at f/8.

33mm focal length, ISO 200, 1/640 second at f/7.1.

33mm focal length, ISO 200, 1/400 second at f/4.9.

Camera Unit Specifications
Image sensor: 23.6 x 15.7 mm CMOS sensor with approx. 12.9 million photosites (12.3 megapixels effective)
Image Sizes: 16:9 - 4288 x 2416, 3456 x 1940; 4:3 - 3776 x 2832, 3072 x 2304, 2592 x 1944, 2048 x 1536, 1280 x 960, 640 x 480; 3:2 - 4288 x 2848, 3456 x 2304; 1:1 - 2848 x 2848, 2304 x 2304
Movie sizes: 1280 x 720, 640 x 480, 320 x 240 at 24 frames/second
Lens: 33mm f/2.5-f/22 lens (50mm equivalent in 35mm format); 9 elements (one aspherical) in 8 groups
Focus system: Contrast-based AF with multi, spot, snap and infinity modes plus focus lock and AF-assist; range - 30 cm to infinity; macro to 7 cm
Digital zoom: Up to 4x (3.6x to movies); 5.9x auto resize zoom
Shutter speed range: 180 seconds to 1/3200 second (upper and lower limits vary with shooting and flash mode); Movies - 1.30-1/2000 second
Exposure metering: 256-segment TTL-CCD metering with multi, centre-weighted and spot modes; AE lock provided
Exposure Compensation: +/- 4 EV in 1/2 or 1/3 EV steps
Exposure bracketing: +/- 2 EV in 1/2 or 1/3 EV steps
ISO range: Auto, Auto Hi, ISO 200, 400, 800, 1600, 3200
White balance: Auto, Multi-P auto, Outdoors, Cloudy, Incandescent, Fluorescent, Manual; White balance bracketing supported
Built-in flash range: 20 cm to 3.0 metres (ISO auto)
Sequence shooting: Max 4 DNG.RAW at 3 fps; M-Cont Plus mode -  HI (JPEG  1280 x 845): Max 30 frames at 24 fps; LO (JPEG 4228 x 2848): Max. 15 frames at 3 fps
Battery life (CIPA rating): Approx. 320 shots/charge
Dimensions: 68.7 x 57.9 x 71.3 mm (camera unit only); 113.9 x 70.2 x 77.1 mm (with camera body)
Weight: 263 grams (camera unit only); 423 grams (with camera body but not including battery, memory card, neck strap, connector cap or lens cap)

RRP: $699 (camera body); $999 (A12 camera unit); GXR camera body plus A12 camera unit - $1599
Distributor: Tasco Sales (Australia); (02) 9938 3244; www.tasco.com.au.