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Canon has re-introduced raw file capture to its top-of-the-range digicam, the PowerShot G9. This alone makes it a significant upgrade to the G7 model, although the G9 has slightly higher resolution (12.1 megapixels vs 10 megapixels) and a larger, 3.0-inch LCD screen. The viewfinder has been shrunk, however, to provide space for the LCD, which adds just over five grams to overall weight.

Compared with the G7, the G9's viewfinder, although similar in appearance, is small and rather cramped. Its 15mm eyepoint isn't particularly comfortable if you're wearing glasses and it covers only about 80% of the sensor's field of view. Fortunately, diopter adjustment of -3.0 to +1.0 diopter is provided to bring it into line with competing cameras and reduce the need for glasses.

The G9 has almost the same physical dimensions and an identical, optically stabilised 6x optical zoom lens to its predecessor. We'd like to have seen a slightly wider angle of view for this lens but it covers a useful range nevertheless. The image stabiliser is very effective. On the basis of our usage of the camera we estimate it could provide up to a three stop advantage over an unstabilised lens.

Interestingly the G9's sensor is marginally larger to take in those extra photosites without reducing actual photosite size (and thereby increasing image noise). It uses the same NB-2LH battery as its predecessor (and also the EOS 400D), a handy feature for photographers looking for a compact digicam to augment their DSLR. The same accessory flash units and lenses can also be used with the new model.

The top panel on the G9 is identical to the G7, with separate dial controls for shooting modes and ISO settings (and an identical range of settings), a flash hot shoe, on/off button and shutter release button with surrounding zoom ring. Layout of other controls is also similar. The image processor is the same DiG!C III chip as in the G7 and, like its predecessor, the G9 offers all the exposure, focusing and shooting controls a keen photographer requires.

Most camera settings are accessed via two buttons. The Function/Set button covers frequently-adjusted controls, including white balance, My Colours, bracketing, flash exposure compensation, metering mode, ND filter, compression, resolution and shooting interval settings. The Menu button accesses less frequently changed parameters, such as AF modes, flash control, digital zoom, in-camera red-eye control, self-timer delay, image stabilisation mode and review times and settings. As in other Canon digicams, quick changes to ISO, flash, drive and focus settings are provided through the arrow pad buttons, while buttons above the arrow pad handle the AF frame selection/erase and exposure compensation/jump settings.

The Face Detection AF and AE functions have been augmented with flash exposure (FE) capabilities plus a new Face Select and Track function to ensure subjects are in focus and correctly exposed at all times. Up to 35 faces can be identified in a scene – a big increase on the nine face limit of the G7. Features carried over from the G7 include the Safety Zoom function and built-in ND filter. The former allows users to extend the camera's zoom range by cropping without interpolation. Up to 24x magnification is available at VGA resolution.

The neutral density (ND) filter reduces the light intensity by three f-stops, allowing photographers to shoot with a wider lens aperture to achieve differential focusing in bright conditions. It can only be used with the P, Tv, Av and M shooting modes as well as for movie capture and is accessed via the Function button.

File Formats
When images are recorded as JPEGs, the G9 applies the same compression ratios as the cheaper PowerShot A650 IS model, which is a little disappointing as the actual compression ratios are a little high. It would have been nice to see lower compression ratios used in this more sophisticated camera. As in the A650 IS, three compression settings are provided although, if the ISO 3200 mode is selected in the Scene menu, resolution defaults to 1600 x 1200 pixels and maximum compression is applied.

Raw shooting is selected via the Recording Pixels sub-menu in the Function menu. Interestingly, raw files taken with the G9 cannot be opened in Digital Photo Professional, the file converter supplied with Canon's EOS DSLR cameras. You can, however, open them in Canon's ZoomBrowser EX (which is supplied with the camera) or the latest version of Adobe's Camera Raw. Other third-party converters should be usable as well, now or in the near future.


Raw files can be converted with the latest version of Adobe's Camera Raw.

You can choose to take RAW+JPEG shots by switching on this function in the Menu. The camera appears to save the two shots separately, just like Canon's DSLRs. Average file sizes for the still shooting modes are as follows:

If you switch to movie mode you can access three resolution/compression settings via the Function menu: 640 x 480 at 30 frames/second in SP and LP modes and 320 x 240 at 30 fps. In this mode, an icon is displayed in the top right corner of the LCD with two green arrows below it. Turning the Control Dial ring around the arrow pad lets you select a couple more movie resolutions:  a 'high-resolution' 1024 x 768 pixel setting and a 'compact' 160 x 120 pixels, both at 15 fps. This menu also contains the settings for the time lapse movie, colour accent and colour swap controls.

In movie mode, the focus and optical zoom position are locked at the values set for the first frame of the sequence but exposure and white balance values will change to suit varying shooting conditions. Touching any of the control buttons may cause the built-in microphone to pick up the sound. Movie recording capacities are shown in the table below.

The G9 will accept the latest Class 6 SDHC memory cards and you can record up to 4GB of video at a time with the high-resolution setting. Time lapse movies covering a period of up to two hours can also be recorded. In addition, the G9 can be used as a stand-alone sound recorder with a maximum recording time of two hours. Sound quality from the test camera was good for a monaural recording.

Handling
Like most compact digicams, the controls on the G9 are rather small, although the shooting mode and ISO dials are knurled for easy operation and click into position positively. The arrow pad stands a little proud of the camera body and the control dial surrounding it moves easily and positively (a little too easily at times). We'd like the shutter button and zoom control to have been slightly larger and the zoom thrust to be longer and feel users with large hands or fingers could find them difficult to operate with any precision.

The grip bar on the front panel is also meagre and, although the camera can be operated one-handedly, when it's held comfortably and securely, some controls are covered by your fingers.  It's nice to see a hard plastic cover on the interface terminal bay (USB 2.0 Hi-Speed, A/V out) but less convenient to have the card slot sharing the battery compartment.

The lens tucks away neatly into the camera body when power is off and extends about 30mm when the camera is in use. Fortunately, it's not visible in the viewfinder at maximum zoom extension.  Optional Wide and Tele converter lenses can be attached via a special conversion ring (not supplied with the camera).

Software
The software bundle contains all the tried-and-true Canon applications: ZoomBrowser EX (Windows), ImageBrowser (Mac), PhotoStitch and CameraWindow DC. ZoomBrowser and ImageBrowser include facilities for downloading image files, editing stills and video movies and printing. These programs are also used for viewing and converting raw files shot with the camera and support a remote triggering function that lets you control the camera's shutter from a connected computer.

Users can also view slideshows, rename individual or multiple files, extract frames from movie clips and export images as screen savers or wallpaper using both applications.  They also support direct emailing of image files by converting them to an appropriate size before transmitting them.  PhotoStitch allows a sequence of shots taken in Stitch Assist mode to be merged into a panorama and saved as a separate file.

Performance
Pictures taken with the test camera were sharp and colourful, although we found a tendency towards blown-out highlights and blocked-up shadows in shots taken in bright, contrasty conditions. Colours were, in the main, natural looking and saturation was elevated but not excessively for a compact digicam. Imatest showed resolution to be good (although not outstanding) and fairly even throughout the camera's ISO range, with some fall-off at ISO 1600. Best resolution was found between f/4.5 and f/6.3, although there was little resolution loss at wider or narrower apertures.

Over-sharpening was not detected; nor did we find any sharpening or compression artefacts in our test shots. Lateral chromatic aberration was shown to be low, although a small degree of coloured fringing was found around the peripheries of shots taken in bright outdoor conditions. Imatest showed some colour shifts in the cyan area, along with elevated saturation in reds and blues. However, skin tones were shown to be close to their target values.

Coloured fringes were revealed at the edges of shots when images were substantially enlarged.

Close-up performance was generally good and digital zoom shots were less artefact-affected than we normally see in small-sensor digicams. Edge-to-edge sharpness was also better than average but we observed noticeable barrel distortion at the widest angle of view, particularly in close-up shots. Lens flare was minimal with contre-jour shots and strong backlighting was competently handled, with little or no effect on exposure metering.

White balance performance was above average, although the auto setting failed to completely remove the orange cast of incandescent lighting. However, it produced excellent results with fluorescent lighting and both the pre-sets and manual measurement delivered close-to-natural colours with both lighting types.

The test camera's flash was able to illuminate an average-sized room at all ISO settings. Throughout the ISO range, flash exposures were generally accurate and well balanced. Image noise was visible in long exposures at ISO 400 and above but only became obvious at the ISO 1600 setting. Even here, shots were usable as long as they were not excessively enlarged.

The test camera powered-up within 1.7 seconds and we measured an average capture lag of 0.5 seconds with both JPEG and raw files. This was reduced to 0.1 seconds with pre-focusing. It took just over three seconds to process a JPEG file and just under four second to process and store a raw file. Shot-to-shot times with flash averaged 2.4 seconds.

In continuous shooting mode the camera recorded two JPEG shots at two frames/second for three shots then slowed to capturing shots at 0.8 second intervals. Using burst mode for raw file capture we recorded 10 shots at 1.5 second intervals with no slowing in the capture rate. It took just under four seconds to process this burst of shots.

Conclusion
Robustly built, comprehensively feature-packed and small enough to slip into a jacket pocket, the PowerShot G9 has a lot in its favour.  Because it offers many of the same shooting controls and supports raw file capture, it would make an excellent compact back-up camera for DSLR users. It would also provide some useful features that are not provided in DSLRs. You get good range of video formats (including widescreen) and facilities for adding sound bites to pictures or making audio recordings.

However, the G9 it is not a beginner's camera and its body is not designed for maximum handling comfort. It's also relatively pricey for a digicam, although the price is largely justified by the camera's image quality and functionality. In knowledgeable hands, it's capable of delivering excellent results.

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SAMPLE IMAGES

Auto white balance with incandescent lighting.

Auto white balance with fluorescent lighting.

 
Short exposure at ISO 80.


Short exposure at ISO 1600.

Long exposure at ISO 100. 

Long exposure at ISO 1600.

Close-up.

Digital zoom.

Backlighting.

Flare was minimal with strong backlighting.

Blown-out highlights were found in JPEG shots taken in bright, contrasty conditions.

Image sensor: 7.6 x 5.7mm CCD with 12.4 milliont photosites (12.1 megapixels effective)
Lens: 7.4-44.4mm f/2.8-4.8 zoom (35-210mm in 35mm format)
Zoom ratio: 6x optical, up to 4x digital
Image formats: Stills – CR2.RAW, JPEG (Exif 2.2); Movies AVI (Motion JPEG/WAV)
Image Sizes: Stills - 4000 x 3000, 3264 x 2448, 2592 x 1944, 1600 x 1200, 640 x 480, 4000 x 2248 (widescreen); Movies – 640 x 480 @ 30 fps (SP and LP) , 320 x 240 @30 fps, 1024 x 768 @ 15 fps, 160 x 120 @ 15 fps plus Time Lapse move at 640 x 480 pixels   
Shutter speed range: 15-1/2500 second
Image Stabilisation: lens-shift type
Exposure Compensation: +/- 2EV in 1/3EV increments
Focus system/range: TTL autofocus with Face Detect, AiAF (9-point), Centre and FlexiZone modes; range 50 cm to infinity, macro 1-50 cm
Exposure metering/control: Evaluative, centre-weighted and spot (centre or AF point) metering; Auto, P., Av, Tv, M, Custom (x2), Stitch Assist, 16 scene modes
ISO range: Auto, ISO 80, 100, 200, 400, 800, 1600
White balance: Auto, Day Light, Cloudy, Tungsten, Fluorescent, Fluorescent H, Flash, Underwater, Custom (x2)
Flash modes/range (ISO auto): Auto, On, Off, Slow Synchro, 2nd-curtain Synchro and Safety FE; Flash output compensation (±2.0 stops in 1/3-stop increments) and Red-Eye Reduction available; range – 0.3-4.0 metres. Hot-shoe for external flash
Sequence shooting:  Approx. 1.5 shots/sec. (Large/Fine mode)
Storage Media: SD/SDHC cards
Viewfinder: real-image zoom with 80% coverage and 15 mm eyepoint; dioptric adjustment: -3.0 to +1.0 dpt
LCD monitor: 3.0-inch low-temperature polycrystalline silicon TFT colour LCD with approx. 230,000 pixels
Power supply:  NB-2LH rechargeable lithium-ion battery
Dimensions (wxhxd): 106.4 x 71.9 x 42.5 mm
Weight: Approx. 320 grams (without battery and card)