The S3 features a f/2.7-3.5 Canon all-glass 12x zoom lens (36-432mm equivalent in 35mm) that makes tack-sharp long telephoto shooting positively practical. By incorporating a UD (Ultra Low Dispersion) lens into the lens element, the incident of chromatic aberration was reduced. Despite its extensive optical range, the lens is ultra-compact and retracts into the camera when it's powered down.

With Canon's optical Image Stabilization technology, users have the flexibility of actually shooting at shutter speeds 2-3 stops lower than would otherwise be possible. The PowerShot S3 IS features multi-mode Image Stabilization - users can choose between Continuous IS (always active), Panning IS (active when vertical camera shake is detected) and a "Shoot Only" IS mode (active when the shutter is pressed all the way.)

The S3 employs a high-speed and variable speed Canon Ultrasonic Motor (USM) to operate the zoom lens mechanism. The silence of the USM is particularly beneficial in movie mode to preserve and enhance the quality of the audio recording. When shooting still images you can zoom in low speed (6 secs to go from wide to tele) or high speed (1 sec.) When shooting movies you can zoom in low speed or medium speed (4 secs to go from wide to tele.)

On the side of the lens barrel you'll find the MF (manual focus) button and the Macro Focus mode button. Macro focus range (in wide angle) is from 3.9 in. to 1.6 ft. (10-50 cm) and covers an area of 4.6 x 3.4 in. (118 x 87 mm). Super Macro focus range (in wide angle) is from 0 to 3.9 in. (0-10 cm) and covers an area of 0.87 x 0.63 in. (22 x 16 mm.)

The S3 is equipped with a single-point TTL AF system that achieves sharp focus quickly and silently. The user can move the AF frame to the area desired by pressing the SET button in record mode. The S3 has a focus-assist illuminator for low light conditions. It also features manual focus override as well as a Focus Bracketing function.

To enhance its flexibility, the PowerShot S3 is compatible with several optional accessories, including WC-DC58A wide-angle, TC-DC58B telephoto and 500D close-up lenses. The dress ring is easily removed to allow the attachment of the LAH-DC20 lens adapter and hood which is required for the wide angle and telephoto auxilliary lenses.

The folks at Lensmate have both a 52mm and a 58mm silver aluminum lens adapter for the S2IS and S3IS. The 58mm allows you to use the 58mm Canon add-on lenses, the 52mm lets you use inexpensive protective filters and clip-in lens caps.

The S3 uses a high-resolution TFT color LCD with 114,000 pixels as the eyelevel finder.

The diopter is adjusted (-5.5 - +1.5 m^-1) with the knob on the side. The DISP button switches between EVF and LCD displays (see below.)

Rotate the LCD all the way forward and flip it around for framing self-portrait shots.

When the LCD is not needed it can be rotated around and positioned "face in" to protect the display from damage or greasy nose prints.

The manual popup E-TTL speedlight has modes for normal auto, auto with red-eye reduction, forced fill, forced off and slow synchro with 1st and 2nd curtain. And Flash Exposure Compensation of ± 2.0 stops in 1/3- stop increments with FE lock function.

The working flash range is:

Normal: 50 cm - 5.2 m (1.6 - 17 ft.) (W),
90 cm - 4.0 m (3.0 - 13 ft.) (T)
Macro: 30 - 50 cm (12 in. - 1.6 ft.) (W)

The Powershot S3 is also compatible with the Canon High-Power HF-DC1 auxiliary flash unit, which increases flash range up to 23 feet.