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Although CMOS image sensors are common throughout Canon's DSLR range, the PowerShot SX1 IS is the first compact camera from Canon to be fitted with a CMOS sensor. Offering 10-megapixel (effective) resolution, the SX1 IS's sensor is significantly smaller than the DSLR sensors. It's partnered by a stabilised 20x optical zoom lens that covers the equivalent of 28-560mm in 35mm format. Although the front of the lens is threaded, it can't accept screw-in filters.

The 5.0-100.0mm Canon lens is equipped with the same ultrasonic motor (USM) and voice coil (VCM) motor technologies as Canon's DSLR lenses and provides fast and almost silent zooming. This is a real advantage for anyone who shoots wildlife or sports. It also supports 'zero macro' shooting, allowing users to capture subjects at almost 1:1 magnification.

The SX1 IS uses lens-shift optical image stabilisation to counteract camera shake. Motion Detection Technology works in parallel with the IS system to minimise blurring due to subject movement. Activated in High ISO Auto mode, Motion Detection is one of a suite of functions introduced with the new DiG!C 4  Image Processor, which is featured in most recent Canon digicams.

Another DiG!C 4 function is improved Face Detection Technology with Face Select & Track and a new Face Self-timer function, which helps to ensure better portrait shots. As well as being able to track moving subjects, the system can adjust exposure levels when the metering is set to evaluative, fine-tune automatic white balance settings and balance flash and ambient lighting.

The Face Self-timer function makes it easy for the photographer to be included in group portraits by delaying the shutter release until the photographer's face is detected in the frame. DiG!C 4  also powers Canon's new i-Contrast control, which balances exposure levels to bring out detail in dark areas of subjects without blowing out highlights.

Sensor

Canon has just provided us with details of the CMOS sensor used in the SX1 IS and confirmed that it has been developed and manufactured at the company's the semiconductor devices factory at the Ayase Office in Kanagawa-ken. It's a 1/2.3-inch type unit with a total photosite count of 11.60 million.

For 4:3 aspect ratio images, the effective pixel count is approximately 10-megapixels, while cropping to produce the 16:9 aspect ratio results in approximately 8.30 million pixels (effective). The pixel pitch is 1.7 mm and the standard primary colour filtration is used (presumably with a Bayer pattern).

The diagram above demonstrates the two aspect ratios of the SX1 IS. (Source: Canon)

Canon claims CMOS sensors in compact digicams provide two advantages: they support high resolution plus high sensitivity with small photosite areas and they enable still cameras to record Full HD movie clips at 1920x1080 pixels and 30 frames/second. In the SX1 IS, the combination of the new sensor and DiG!C 4  processor provide a new electronic teleconverter function that doubles the optical zoom range without image quality deterioration (although resolution is reduced to 2-megapixels) and is usable during movie recording.

The SX1 IS only captures still images as JPEGs, offering seven image size settings (including two 16:9 'widescreen' sizes) plus three compression levels. Typical image sizes are shown in the table below.

As well as supporting continuous shooting speeds of up to 4 frames/second, the SX1 IS also allows users to record Full High Definition (1920x1080) movies at 30 frames/second with stereo sound. It also supports VGA and QVGA video recording at the same frame rates with typical recording capacities shown in the table below.

To make video capture even easier and more accessible, the SX10 IS allows you to initiate movie recording from any shooting mode by simply pressing the large button on the rear panel. A second push stops recording.

The diagram above demonstrates the difference in resolution between standard VGA video and Full HD video. (Source: Canon)

Autofocusing continues while video is being captured and adjustments will be made to exposure levels and white balance, if required. Face detection also engages automatically when the 4:3 aspect ratio is selected.

However, intending purchasers should note that no HDMI cable is supplied with the camera so, if you want to playback HD video clips directly on a TV set you must provide your own connecting cable. 

Physical Characteristics
Like most ultra-zoom digicams, the SX1 IS looks and feels like a down-sized DSLR. Stylishly, it owes a lot to the superseded PowerShot S5 IS model, although it's larger and approximately 110 grams heavier. Features that attracted buyers to the S5 IS, such as the vari-angle LCD screen and hot-shoe flash attachment, are included in the new model.

Front view of the SX1 IS with power switched on.

Build quality is generally very good. Despite being made of plastic, the camera body feels robust and all joints and compartment covers are nicely finished. The grip is large enough to be comfortable for average-sized (and larger) hands and it positions the right index finger well for operating the shutter button and zoom control.

Rear view with the vari-angle monitor rotated to protect the LCD screen.

The little finger of the right hand slips under the body to provide support for one-handed shooting. No texturing is applied to the rubberised surface of the grip, which is matte and quite smooth and could prove slippery in damp or humid conditions. There's a dimpled thumb rest patch at the back of the grip, which positions the thumb close to three button controls.

Two views of the SX1 IS from above, showing the differences in lens barrel length between the wide (top) and tele (below) positions.

The lens barrel protrudes about 40mm from the rest of the camera body and has a smooth, polished finish. The lens itself extends approximately 17 mm when the camera is switched on and a further 33 mm when you move from the wide to the tele position. The zoom lever for the lens provides smooth transitions across the focal length range and it's easy to make precise magnification settings (a factor not found often in digicams). A clip-on cap fits onto the lens but no tether is provided to prevent it from being mislaid.

Just above the lens barrel and on either side of the flash are twin microphones for the stereo sound recording, both in movie mode and for stand-alone capture or adding voice clips to still images. Between the left microphone and the shutter button is the sensor for the wireless remote controller that is included in the camera kit. On the opposite side of the front panel is a large LED lamp, which provides illumination for the AF assist, red-eye reduction and self-timer functions.

The top panel carries the mode dial, on/off switch and pop-up flash, plus the manual flash pop-up button. Most of the rear panel is covered by the 2.8-inch vari-angle widescreen LCD monitor, which has an average resolution of 230,000 dots. The LCD is larger than average and sports a 16:9 aspect ratio to match the camera's widescreen video capabilities. It's also one of the clearest, brightest monitors we've seen on a compact digicam to date - despite having a resolution of only 230,000 dots.

Two brightness settings are provided, neither of which can compensate for the glare of a direct sunlight on a bright sunny day. Fortunately the adjustment flexibility provided for the screen will let you get around most potential problems - and there's a viewfinder to back you up, if you need it.

The EVF (electronic viewfinder) is located just above the monitor and offers an adjustment of -6.0 to +2.0 dioptres. Unlike the LCD monitor, the EVF has 148,000-dot resolution and looks quite granular. It also has a greenish-blue colour cast. A firm rubber surround on the eyepiece makes it more comfortable to use than many EVFs and provides some protection for wearers of glasses. However, if asked to choose between the LCD and EVF for framing shots, you'd definitely choose the former for accuracy and clarity.

Left of the viewfinder are the Print/Share and aspect ratio buttons, the latter swapping between 4:3 and 16:9 formats. Right of the viewfinder is a large button for switching on movie recording. Ranged in an arc around the back of the grip are three additional buttons that access the playback, exposure compensation and AF frame selection (the last two control the Jump function and single image erase in playback mode).

The arrow pad sits below these buttons. It's the familiar Canon design with a rotating Control Dial and central Func./Set button plus horizontal and vertical 'buttons' for setting the macro/ISO and manual focus/drive controls. Below the arrow pad are the Display and Menu buttons.

The side panel carries recessed compartments for the DC-in/AV-out ports and USB/HDMI ports. Both have hard plastic covers attached by rubber hinges. The SD card slot lies under another hard plastic cover lower down the side panel. It attaches with a metal hinge and opens with a push and lift movement.

The batteries slot into a dedicated compartment in the base of the camera that is opened with a push and slide movement. The tripod socket is located beside this compartment, close to the centre of the rear panel. Strap loops at each end of the top panel provide attachments for the supplied neck strap.  

Shooting Controls
The SX1 IS's control suite will suit both knowledgeable and novice photographers. For the former, the mode dial carries the required P, Tv, AV and M settings plus a C (Custom) memory bank for saving a selection of frequently-used settings. This function is handy for saving settings like the self-timer and continuous shooting modes, which default to off when the shooting mode is changed or the power is switched off.

For novice users, the SX1 IS carries a full auto mode plus a reasonably comprehensive suite of scene pre-sets. Some of these are located on the mode dial for quick access while the rest are found in the Scene sub-menu, which is also accessed via the mode dial. The former include pre-sets for Portrait, Landscape, Night Snapshot and Sports modes while the latter include: Night Scene, Indoor, Sunset, Foliage, Snow, Beach, Fireworks, Aquarium, Long shutter, ISO 3200, Colour Accent and Colour Swap.

The menu system is similar to other Canon digicams, with the Func/Set button in the centre of the arrow pad accessing the white balance, My Colours, bracketing, flash exposure adjustment, metering pattern, video quality and image size and quality settings. The Menu button takes you to all other controls. The settings you can access depend on the shooting mode you've selected. In the full auto and scene modes you can only adjust image size and quality, whereas in the P, Av, Tv and M settings everything is adjustable. You can adjust white balance and apply My Colours settings in the Panorama and Movie modes. Movie resolution options depend on whether you've selected widescreen or 4:3 via the aspect ratio button.

As in other recent Canon digicams, the My Colours sub-menu provides 11 colour selections: vivid, neutral, sepia, B&W, positive film, lighter skin tone, darker skin tone, vivid blue, vivid green, vivid red and a Custom Colour setting that lets you adjust contrast, sharpness or saturation settings and make subtle adjustments to image colours. Canon's i-Contrast dynamic range control function is also provided.

The SX1 IS provides the same focusing settings as Canon's other advanced digicams, with a choice between single shot and continuous AF settings plus three AF frame options: centre, face detect and Flexizone. The centre and face detect are self-explanatory, while Flexizone lets the user move the AF frame around the screen. An additional Face Select & Track feature allows the user to designate a face for the AF frame to follow. FaceSelf-Timer

Playback and Software
Pressing the Playback button on the rear panel displays the last image taken. Playback options are essentially the same as other Canon digicams. The camera supports single, 12-frame index and video playback, playback zoom of up to 10x, focus check playback (with magnification), slideshows with three selectable transition effects and the standard range of Jump options.

In playback mode you can also erase or protect single shots or a selection of images, allocate images to categories, resize, rotate and trim images, add sound memos up to a minute long to selected shots or apply red-eye corrections. Both i-Contrast and My Colours adjustments can be applied to images in playback mode. Images can be tagged for automatic printing via a dedicated Print menu and the camera is fully PictBridge compatible.

The software bundle includes ZoomBrowser EX 6.2 (Windows) and ImageBrowser 6.2 (Macintosh) for organising and editing images, movies and slideshows, or creating and printing digital photo albums. The PhotoStitch panorama stitching application is also provided. The SX1 IS also supports driverless transfer to Windows XP and Macintosh OS X, along with MTP for image and movie transfers to Windows Vista. 

Performance
Pictures taken with the test camera were sharp and clean with natural-looking colours. Pastel colours retained the required degree of tonal subtlety and primary colours were strong and bright with the slightly elevated saturation that typifies compact digicams. Plenty of detail was recorded and the dynamic range in shots of contrasty subjects was wider than you would expect from a camera with such tiny photosites. An example is shown below.

Dynamic range coverage; 85.2,, focal length, ISO 100, 1/250 second at f/8.

Imatest showed resolution to be up to expectations but revealed some edge softening, particularly at shorter focal lengths. Best performance was at the shorter focal lengths and with wider lens apertures. The graph below shows the results of our tests. Note: aperture settings are given as a range because of variations at different focal length settings.

Our tests also indicated a relatively low level of post-capture processing, which resulted in very clean image files. Resolution began to fall off at ISO 400 and had declined sharply by ISO 1600. The graph below shows the results of our tests.

Colour accuracy was fair in our Imatest assessments, which revealed the slightly elevated saturation, particularly in reds and blues, that is common in small-sensor digicams. Skin hues were slightly off the mark and Imatest also showed some colour drifts in orange and cyan hues.

Lateral chromatic aberration ranged from moderate to serious in our Imatest tests and we found some colour fringing when shots were enlarged to 100%. Fringing was apparent with both the wide and telephoto focal lengths and it was more pronounced towards the edges of shots than near the centre. Two examples are shown below.


Coloured fringing from a wide-angle shot. This 100% enlargement is cropped from near the edge of the frame.

Coloured fringing from a telephoto shot. This 100% enlargement is cropped from near the centre of the frame.

Backlit subjects were handled with ease and we found little evidence of flare or ghosting in backlit shots taken under typical shooting conditions (i.e. without the sun shining directly into the lens). Digital zoom shots were much sharper and less artefact-affected than Photo Review commonly sees in extended-zoom digicams we review.

Close-up performance was impressive, thanks to the camera's 'zero macro' capabilities, which will focus on subjects that almost touch the front element of the lens. Depth-of-field is very limited in such shots and you must guard against allowing dusty or sticky items to come in contact with the front element of the lens. The effectiveness of the image stabilisation system can be seen by checking the shutter speeds for the shots in the Sample Images section at the end of this review.

The flash was capable of illuminating an average-sized room at all ISO settings and produced evenly-balanced exposures up to ISO 1600. Low-light performance was very good for long exposures between ISO 100 and 400, where traces of image noise became visible. With this setting - and at ISO 800 - noise would be unlikely to interfere with print quality at enlargements up to A4 size. At ISO 1600, both colour and pattern noise were visible in night shots and some blotchiness was apparent in flash exposures.

Movie quality was very good at the 1920 x 1080 pixel setting but less impressive (although still adequate) at lower resolutions, particularly in dim lighting where noise was evident. The quality of the stereo audio was also a cut above average and on a par with a typical digital camcorder. 

The auto white balance failed to eliminate the orange cast of incandescent lighting but produced close-to-neutral colours under fluorescent lights. With both types of lighting, the pre-sets delivered neutral colours, as did manual measurement.

Overall response times were about average for the latest digicams. The test camera powered up ready for shooting in approximately half a second and shot-to-shot times averaged 1.8 seconds without flash and approximately 3.5 seconds with. On average, it took 3.3 seconds to process each image file.

We measured an average capture lag of 0.3 seconds, which changed to almost instantaneous capture when shots were pre-focused. The continuous shooting mode recorded 10 shots in 2.3 seconds. Image processing appears to be on-the-fly as it took only 3.5 seconds to process each burst of 10 shots.

The alkaline batteries supplied with the test camera still had power remaining at the end of our tests, which involved just over 200 shots. This is very good, since the supplied batteries are only rated for 160 shots. 

IMATEST GRAPHS

SAMPLE IMAGES

Auto white balance with incandescent lighting.

 Auto white balance with fluorescent lighting.

Close-up. 5mm focal length, ISO 100, 1/60 second at f/3.5.

Digital zoom. 100mm focal length, ISO 100, 1/40 second at f/5.7.

4:3 aspect ratio comparison: 5mm focal length, ISO 100, 1/807 second at f/4.

4:3 aspect ratio comparison: 100mm focal length, ISO 100, 1/636 second at f/5.7.

16:9 aspect ratio comparison: 5mm focal length, ISO 100, 1/250 second at f/8.

16:9 aspect ratio comparison: 100mm focal length, ISO 100, 1/400 second at f/8.

ISO 80, 15 second exposure at f/2.8; 11.6mm focal length.

ISO 1600, 2 second exposure at f/2.8; 11.6mm focal length.

Available light, hand-held exposure. 6.3mm focal length, ISO 1600, 1/4 second at f/2.8.

Flash exposure; 37.5mm focal length. ISO 100, 1/60 second at f/5.

Flash exposure; 37.5mm focal length. ISO 1600, 1/60 second at f/5.

Backlighting. 16:9 aspect ratio, 9.9mm focal length, ISO100, 1/600 second at f/8.

Image sensor: 6.16 x 4.62 mm CMOS imager with 11.8 million photosites (approx. 10-megapixels effective)
Lens:  5.0-100.0mm f/2.8-5.7 Canon zoom lens (28-560mm in 35mm format)
Zoom ratio: 20x optical, up to 4x digital
Image formats: Stills – JPEG (Exif 2.2); Movies - MOV (Image Data: H.264; Audio Data: Linear PCM stereo)
Image Sizes: Stills – 3648 x 2736, 2816 x 2112, 2272 x 1704, 1600 x 1200, 640 x 480; Widescreen: 3648 x 2048, 1920 x 1080; Movies – 1920 x 1080, 640 x 480 and 320 x 240, all at 30 fps
Shutter speed range:  15-1/3200 second
Image Stabilisation: Optical (Lens Shift Type)
Exposure Compensation: +/- 2EV in 1/3EV increments
Focus system/range: TTL Autofocus (Single/Continuous) incl. Face Detect with movie support, Centre, Flexizone, Manual; range – 50 cm to infinity; macro 10-50 cm; super macro – 0-10 cm
Exposure metering: Evaluative, Centre-weighted average, Spot metering
Shooting modes: Auto, P (Program), Tv (Shutter Priority), Av (Aperture Priority), M (Manual), C (Custom), Portrait, Landscape, Night Snapshot, Sports, Special Scene (Indoor, Night Scene, Sunset, Long Shutter, Foliage, Snow, Beach, Fireworks, Aquarium, ISO 3200, Colour Accent, Colour Swap), Movie Standard, Movie HD
ISO range: Auto, High ISO Auto, ISO 80, 100, 200, 400, 800, 1600
White balance: Auto, Daylight, Cloudy, Tungsten, Fluorescent, Fluorescent H, Flash, Custom
Flash modes/range (ISO auto): Auto, on, off, Red Eye Correction, Red Eye Reduction, Slow Synchro, Second Curtain Synchro, FE Lock, Safety FE; range - 50cm to 4.8 m (W), 1m to2.6 m (T)
Sequence shooting:  Up to 4 fps with focus fixed at first frame; approx. 1.1 fps with AF; approx. 1.2 fps in Live View continuous mode
Storage Media: SD/SDHC cards
Viewfinder: 0.40-inch, 148,000-dot TFT electronic viewfinder with dioptric adjustment of -6.0 to +2.0 dpt
LCD monitor: 2.8 inch vari-angle LCD monitor with approx. 230,000 dots
Power supply:  4x AA batteries (alkaline, NiMH or Lithium); CIPA rated for approx. 420 shots/charge with NiMH batteries or approx. 160 shots with the supplied AA alkalines
Dimensions (wxhxd): 124 x 88.3 x 86.9 mm (ex. protruding parts)
Weight: Approx. 560 grams (without batteries and card)