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Canon's PowerShot SX100 IS has many of the features of the popular S5 IS model but boasts a smaller, lighter body and significantly lower price tag. Boasting an 8-megapixel CCD imager and 10x optical zoom lens with optical image stabilisation, the SX100 IS sports the latest DiG!C III image processor, which includes Face Detection technology plus support for ISO 1600 sensitivity. The 2.5-inch LCD monitor is fixed and has 172,000-pixel resolution and the camera has obviously been designed to provide performance and functionality at an economy price.

The SX100 IS's plastic body is manufactured in black and silver. With smart 'retro' styling reminiscent of Canon's compact film cameras, it's solidly built, although the silver version we reviewed looked rather plasticky. The shutter release side of the camera is contoured to accommodate the battery compartment, which holds two AA cells plus an SD card slot. This grip bulge – and the thumb rest on the rear panel – have smooth surfaces that can be insecure when your hands are sweaty.

Batteries and SD memory card share the same compartment in the base of the camera, which has a hinged, push-out-and-lift cover that is reasonably sturdy. The SX100 IS can also use SDHC and MMC memory cards. A plastic-lined tripod socket sits slightly off-centre next to the battery compartment. USB, DC-in and A/V out terminals lie beneath a tethered, solid plastic cover on the side panel, just below the shutter button and mode dial. The wrist strap loop sits just below.

The mode dial carries the standard Auto, P, Tv, Av and M settings plus positions for shooting panoramas and dedicated modes for shooting portraits, landscapes, night snapshots and kids & pets plus a SCN mode, which accesses a sub-menu containing settings for the night scene, indoor, foliage, snow, beach, fireworks and aquarium pre-sets. Video movie recording modes are also engaged via a special mode on this dial.

The shutter button is large and located atop the grip moulding (which is relatively small). It's surrounded by the zoom lever with a small on/off button nearby. The pop-up flash is situated directly above the lens, which retracts into the camera body when power is off.  Just over half of the rear panel is covered by the LCD screen. Below it lie buttons for accessing direct printing, face selection, display and menu functions.

A rotating dial replaces the traditional arrow pad but offers similar functions. On the review camera it moved a little too readily, making it easy to mis-set controls inadvertently. Quick access to focus pre-sets, ISO, flash and drive/self-timer modes is provided via this dial when it is pressed down at the four quadrants. The central Func./Set button accesses and locks in the white balance, My Colours, flash output, metering mode, compression and resolution settings. A quick review button sits above the control dial, with an exposure compensation/delete button below it.

When Manual exposure mode is selected you can toggle between the aperture and shutter speed settings with the +/- button then change settings with the rotating dial. Ten lens aperture settings are provided at wide angle, ranging from f/2.8 to f/8. At full zoom extension, only six aperture settings are provided, starting at f/4.3 and ending at f/8.

You can overlay a 3x3 grid frame or 3:2 aspect ratio guide on the LCD in shooting mode and opt for a Detailed display with shooting information, which varies according to the mode selected.

Still images are recorded as JPEG files, with seven size options and three compression levels provided. The table below shows typical file sizes. (Note: both file sizes and compression ratios are the same as the Ixus 860 IS model and compression is slightly lower than the PowerShot A650 IS.)

Video compression rates are marginally higher than the Ixus 860 IS but the same sizes and frame rates are provided in both cameras. The focus and zoom settings are fixed at the start of a video clip to prevent camera noise from being picked up by the built-in microphone. However, you can use the digital zoom – although quality will suffer. Typical video sizes are shown in the table below.

Playback options are standard for an advanced digicam and include single and index playback, playback zoom with up to 10x magnification and slideshow playback. Selecting detailed playback displays a thumbnail image with shooting data and a small brightness histogram.

You can play slideshows with or without fade-in/out transitions, resize shots and correct red-eyes in flash shots – all with the camera menu. Despite the low resolution of the LCD, al playback modes were easy to use and effective. Images can be erased singly or collectively, rotated, protected or marked for automatic printing. You can also attach a sound bite up to a minute long to selected shots.

Performance
Pictures taken with the test camera were sharp but rather contrasty. Exposures were pitched to record highlight detail, leaving shadows to block up. Autofocusing was fast and accurate in bright conditions – and almost as good in low light. The image stabilisation system proved effective in dim lighting; we estimate it provided a 2-3 stop advantage at long zoom settings.

Colour accuracy was generally good, although saturation was elevated, particularly in the reds. We found some colour shifts in cyan and yellow/green hues. Skin tones, however, were close to the mark. Imatest showed resolution to be slightly below expectations and revealed a progressive loss of resolution from ISO 800 on.

Lateral chromatic aberration ranged from low to moderate, depending on lens aperture setting. Best results were obtained between f/4.0 and f/5.6. Coloured fringes were found along the edges of outdoor shots but they only became noticeable with 100% magnification and were less severe than we've found with some other digicams we've tested.


Coloured fringes were visible at the edges of shots with 100% magnification.

Noise was low at ISO 80 and 100 but rose progressively thereafter, becoming unacceptable by ISO 800. Interestingly, noise in long exposures (13-15 seconds) at ISO 400 was relatively low, although at ISO 800 it had become visible and by ISO 1600, both colour and pattern noise were severe – and very obvious. With shorter exposures (including flash shots), image noise was less obvious, although shots taken at ISO 1600 had a blotchy look and visible granularity.

Barrel distortion was noticeable at the widest angle of view but disappeared by mid-way through the zoom range. A touch of pincushion distortion was seen in shots taken at full tele zoom. Digital zoom shots were slightly soft and artefact-affected. Close-ups were competently handled but high saturation produced a lurid effect with some subjects.

The auto white balance produced neutral colour rendition under fluorescent light but failed to remove the orange cast of incandescent lighting. The pre-sets delivered neutral colours with both lighting types but we were unable to obtain neutral colour with the manual white balance under incandescent lighting. Flash exposures were generally well balanced between ISO 200 and ISO 1600. However, under-exposure occurred at lower ISO settings.

The test camera took just over two seconds to power-up and extend its lens and roughly the same time to shut down. We measured a consistent capture lag of 0.5 seconds, which switched to instantaneous capture with pre-focusing.  Shot-to-shot times averaged just under two seconds, extending to around five seconds with flash. The continuous shooting mode recorded shots at 0.7 second intervals and it took 3.5 seconds to process a burst of 10 high-resolution shots.

Conclusion
The PowerShot SX100 IS is built to a price and it shows in the body construction more than in the feature set provided. With an RRP $250 less than the PowerShot S5 IS – which has the same resolution but is better built and has a marginally more sophisticated feature set – it represents a good choice for photographers who want a long-zoom digicam with decent performance at an affordable price. But, if you can afford the extra money – which may not be as much at street price level – the S5 IS would be the better buy.

IMATEST GRAPHS

Resolution at low sensitivity.


Resolution at ISO 1600.

SAMPLE IMAGES

 
Auto white balance with incandescent light.


Auto white balance with fluorescent light.


Close-up.


Digital zoom.


Short exposure time at ISO 80.


Short exposure time at ISO 1600.


Long exposure (13 seconds) at ISO 1600.

Image sensor: 5.76 x 4.29mm CCD with 8.? Million photosites (8.0 megapixels effective)
Lens: 6.0-60mm f/2.8-4.3 zoom lens (36-360mm in 35mm format)
Zoom ratio:  10x optical, approx 4x digital
Image formats: Stills – JPEG; Movies – Motion JPEG/WAV (monaural)
Image Sizes: Stills - 3264 x 2448, 3264 x 1832, 2594 x 1944, 2048 x 1536, 1600 x 1200, 640 x 480, 1600 x 1200 with date imprint; Movies -
Shutter speed range:  15-1/2500 second
Image Stabilisation: Optical
Exposure Compensation: +/- 2 stops in 1/3-stop increments
Focus system/range:  TTL autofocus with Face Detect and manual focus; range 50 cm to infinity; macro 1-50 cm
Exposure metering/control: Evaluative, Centre-weighted average, Spot metering; P, A, S, M shooting modes plus 11 scene pre-sets and Stitch Assist
ISO range: Auto, Hi ISO Auto, ISO 80, 100, 200, 400, 800, 1600
White balance:  Auto, Daylight, Cloudy, Tungsten, Fluorescent (x2), Underwater, Custom
Flash modes/range (ISO auto): Auto, On, Off, Slow-synchro (Red-eye reduction is available); range 50 cm to 3.0 m; +/- 2EV compensation available
Sequence shooting:  Normal: Approx. 1.3 shots/sec, AF: Approx. 0.8 shots/sec (Large/Fine)
Storage Media: SD/SDHC/MMC cards
Viewfinder: Real-image optical zoom
LCD monitor: 2.5-inch Low-temperature polycrystalline silicon TFT colour LCD with approx. 172,000 pixels
Power supply:  2x AA batteries (AA or NiMH)
Dimensions (wxhxd): 108.7 x 46.7 x 71.4 mm
Weight: Approx. 265g (without batteries and card)