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Canon Powershot G6 By: Dave Etchells The next generation of Canon's popular "G" model updates the line with a larger, 7.1-megapixel CCD and a redesigned camera body. Select a topic Reference: Datasheet G6 Sample Images G6 Imatest Results G6 Photo Gallery! --------------------------------- 1. Intro and Highlights 2. Changes from the Canon PowerShot G5 3. Executive Overview 4. Design 5. Viewfinder 6. Optics 7. Exposure & Flash 8. Shutter Lag & Cycle Time Tests 9. Operation & User Interface 10. Camera Modes & Menus 11. Image Storage & Interface 12. Video, Power, Software 13. Test Results & Conclusion --------------------------------- Print-Friendly Review Version Additional Resources and Other Links Reader Comments on G6 Review --------------------------------- Digital Camera Comparometer (TM) --------------------------------- <-- Digital Cameras (Home) <-- Digital Camera Reviews Index <<Viewfinder :(Previous) | (Next): Exposure & Flash>> Page 6:Optics Review First Posted: 09/28/2004

Optics

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The G6 features a built-in, 4x, 7.2-28.8mm zoom lens, equivalent to a 35-140mm lens on a 35mm camera. This amounts to a range from average wide-angle to pretty good telephoto coverage. 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 1.6 feet (50 centimeters) to infinity in Normal Focus mode. Macro mode features a focus range of 2.0 inches to 1.6 feet (5 to 50 centimeters). The aperture adjusts automatically or manually, with an f/2.0-3.0 to f/8 range, depending on the zoom setting. (The value of the very fast f/2.0 maximum aperture is not to be underestimated. It'll let you use shutter speeds twice as fast as the more common f/2.8 lenses usually found on digicams, a significant benefit in many situations.) An internal neutral density filter can be deployed via a menu option to cut the light transmission by a factor of 8 (3 f-stops), permitting the use of wider apertures or slower shutter speeds in bright conditions.

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. Scrolling the Main dial back and forth controls the focusing distance, which is displayed via a bar graph on the LCD monitor. The distance marks on the focusing scale are shown 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 turn the Main dial 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. While the manual focus system works pretty well, I'd really like to see more numeric distance markings on the scale: In low light conditions, I've sometimes found it necessary to set focus by estimating the distance, but the limited number of specific distance markings on the G6's manual focusing scale make it difficult to do this. Also, the focus seems to adjust very slowly when in manual focus mode, to the point that I sometimes found it a little frustrating, when it seemed that I was rotating the command dial with very little apparent effect in the focus setting.

When shooting in Autofocus mode, the G6 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. Given that the camera is continuously adjusting the focus in Continuous AF mode, you'd expect the shutter delay to be less. (Since the lens ought to be close to optimum focus most of the time.) Like most cameras with continuous autofocus modes though, the G6's shutter lag was actually slightly longer in Continuous AF mode in my tests. It might thus be useful for tracking moving subjects (which IR has no quantitative way of testing), but don't look to it as a means to improve shutter response.

The G6 features Canon's "FlexiZone Autofocus" system, which lets you change the focus area by scrolling smoothly up or down, right or left. The AF area can be positioned anywhere within a central area covering roughly 60 percent 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 Four-Way Arrow pad, you can then move the AF box smoothly around the frame. When you have it positioned where you want, press the SET button again to deselect 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 or yellow if it's not. Through the Record menu, you can choose to have the Spot Metering function use this same area for its exposure determination, using the Spot AE Point submenu option.

Canon's earlier G3 model was the first camera I had seen with an Auto Focus Bracketing feature on it, and I'm pleased to see it return on the G6. 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 one to three 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.

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 approximately 16x. (The 16x total zoom corresponds to 4x optical plus roughly 4x digital.) Digital Zoom is not available when shooting with the G6'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.)

Like the G3 and G5, the G6 accommodates several optional conversion lenses via a lens adapter kit, so you can extend your camera's wide angle or telephoto capabilities with high-quality optics. The adapters attach via a bayonet mount on the lens barrel, and 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 and reveal the flanges of the bayonet mount.