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Canon PowerShot G3 The third generation of Canon's popular G model retains last year's 4 megapixel CCD, but brings a 4X zoom lens and a host of other improvements. Select a topic Reference: Datasheet G3 Photo Gallery! G3 Sample Images --------------------------------- 1. Intro and Highlights 2. Executive Overview 3. Design 4. Viewfinder 5. Optics 6. Exposure & Flash 7. Shutter Lag & Cycle Time Tests 8. Operation & User Interface 9. Camera Modes & Menus 10. Image Storage & Interface 11. Video, Power, Software 12. Test Results & Conclusion --------------------------------- Print-Friendly Review Version Additional Resources and Other Links Reader Comments on G3 Review --------------------------------- Digital Camera Comparometer (TM) --------------------------------- <-- Digital Cameras (Home) <-- Digital Camera Reviews Index <<Viewfinder :(Previous) | (Next): Exposure & Flash>> Page 5:Optics Review First Posted: 9/16/2002

Optics

The G2 features a built-in, 4x, 7.2-28.8mm zoom lens (equivalent to a 35-140mm lens on a 35mm camera). When the camera is powered on, the lens telescopes out from the camera body into its operating position (extending about an inch from its stowed position), then retracts again when the camera is shut off. A plastic lens cap protects the lens when not in use, and features a small tether to attach it to the camera body. Focus can be automatically or manually controlled, with a range of 2.3 feet (70cm) to infinity in Normal Focus mode. Macro mode features a focus range of 1.5 inches to 2.4 feet (3.8 to 70cm). (Those focus figures are unconfirmed with Canon at this point, I'll recheck once I receive a production unit to test.) The aperture adjusts automatically or manually, with an f/2-f/8 range, depending on the zoom setting.

Manual focus is activated by depressing the Manual Focus (MF) button on the back of the camera. Once pressed, a distance indicator appears on the LCD monitor, providing a reference scale for focusing. The Up and Down arrows of the Omni Controller control the focusing distance, which is displayed on the LCD monitor. The focus distance is reported in metric or English units, as selected in the setup menu. The readout shows meters or feet, centimeters or inches, depending on the range. I found the roughly 2x viewfinder enlargement that accompanies Manual Focus mode very helpful in setting focus. As soon as you press the Up or Down arrows to adjust focus (while in MF mode), an enlarged portion of the subject appears in the center of the LCD display, making it easier to determine exact focus. (In a side note to the Canon engineers, I'd really like to see even more magnification than this: How about 3x, or perhaps an option in the setup menu to switch between 2x and 4x for MF-assist magnification.)

When shooting in Autofocus mode, the G3 offers both Continuous and Single Autofocus functions. In Continuous mode, the camera is constantly adjusting focus, even when the Shutter button is not depressed. In Single mode, the camera focuses only when the Shutter button is depressed halfway, which helps to conserve battery power. The Pan Focus (hyperfocal) mode of the G2 is missing, but you can achieve much the same effect by working in aperture priority mode, selecting a smallish aperture, and then manually focusing a little ways in from infinity. (It'd be helpful if Canon would tell us what the hyperfocal settings are for various aperture settings, at wide angle and telephoto focal lengths.)

The G2 offered the ability to select from one of three main focus areas, but the G3 goes quite a bit farther. Borrowing a page from their video division, Canon has implemented what they call "FlexiZone Autofocus" in the G3. This means that the focus area can be scrolled smoothly up or down, right or left, to be positioned anywhere within a central area covering roughly 60% of the frame. To move the AF area, press the SET button while in Record Mode. The central box that marks the AF area will turn green, indicating that it is selected. Using the up/down, left/right arrows on the Omni Controller, you can move the AF box smoothly around the frame. When you have it positioned where you want, press the SET button again to unselect it. Once the focus point is set and the picture is framed, pressing the Shutter button halfway will turn the box green if the selected area is in focus and yellow if it's not. Through the Record menu, you can choose to have the the Spot Metering function use this same area for its exposure determination, using the Spot AE Point submenu.

Digital Zoom is activated through the camera's Record menu and is operated with the same controls as the optical zoom. The amount of total zoom (optical plus digital) is reported in the top right corner of the LCD monitor whenever digital zoom is engaged, and can go as high as 14x. (The 14x total zoom corresponds to 4x optical plus 3.5x digital.) Digital Zoom is not available when shooting with the G3's Movie mode, or when using the RAW file format. (It's important to note that digital zoom simply enlarges the center of the CCD image, resulting in some loss of image quality in the form of reduced image sharpness that's directly proportional to the amount of digital zoom used.) The G3's digital zoom operates the same as that on the G2, producing a continuous zoom range up to 14x, working in cooperation with the 4x optical zoom lens.

Like the G2, the G3 accommodates several optional lens converters via a lens adapter kit, so you can extend your camera's wide angle or telephoto capabilities with high-quality optics. What's different on the G3 is that these adapters attach via a bayonet mount on the lens barrel, rather than the body threads used on the G2. A small button below the lens on the front of the camera releases a catch, letting you remove the cosmetic collar surrounding the lens barrel, revealing the flanges of the bayonet mount. I haven't seen the new accessory lenses Canon will be offering for the G3 yet, but know that they'll offer a good bit wider range overall than did the ones for the G2. With the new adapter lenses, the total equivalent focal length range of the G3 will run from 24.5 mm at the extreme wide angle end to 245 mm on the telephoto side. (The G2's accessory lenses gave it a range of roughly 27 to 150 mm.)

Auto Focus Bracketing (!)

The G3 is the first camera I've seen with this feature on it. Auto Focus Bracketing (AFB) snaps three exposures in rapid succession, shifting the focus slightly after each. This function is accessed through the FUNC button's sub-menus. You can set the focus step size from 1 to 3 in arbitrary units, by depressing the FUNC button, scrolling to the AFB option with the Omni Controller, and then using the Omni Controller again to choose the amount of variation between shots. Depress the Set button, then fully depress the Shutter button to start the series. The camera makes all three exposures with just one press of the Shutter button. (Pretty slick.)

Confused by Apertures and Depth of Field? - Do you know how to use "Front Focus" or "Back Focus" to get *all* your subject in focus? Visit our free Photo Lessons area and click on the lessons "Focusing Up Close" and "Selective Focusing Outside!"