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Canon PowerShot Pro90 IS An impressive update to the PowerShot "Pro" line, with a 10x optically stabilized zoom lens and 2.6 megapixel CCD! Select a topic Reference: Datasheet PowerShot Pro 90 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, & Hardware 12. Test Results & Conclusion --------------------------------- Print-Friendly Review Version Additional Resources and Other Links Reader Comments on PowerShot Pro 90 Review --------------------------------- Digital Camera Comparometer (TM) --------------------------------- <-- Digital Cameras (Home) <-- Digital Camera Reviews Index <<Viewfinder :(Previous) | (Next): Exposure & Flash>> Page 5:Optics Review First Posted: 2/6/2001

Optics
The Pro90 is equipped with a 7-70mm, 10x zoom lens, the equivalent of a 37-370mm lens on a 35mm camera. Optical zoom is controlled by a notched zoom ring at the end of the lens barrel. This zoom-control ring is a "fly by wire" control, in that it doesn't actuate the lens mechanically, but rather acts as a toggle control to activate a motor that does the zooming for you. We found this slightly disconcerting at first, our unconscious expectation being that the ring would operate the lens directly. Ultimately though, it's no different than the use of rocker controls to actuate the lens mechanism on other cameras, and was easy enough to adapt to after only a little use.

The lens aperture ranges from f/2.8 to f/8.0, and can be manually or automatically set. Focus ranges from 3.9 inches (10cm) to infinity at maximum wide angle, or 3.3 feet (1 meter) to infinity at maximum telephoto. Thus, with the closest range at 3.9 inches (10cm), there is no macro mode available. Closeup photography is achieved by placing the lens at the full wide-angle setting and moving closer to the subject.

Focus options include both automatic and manual control. The camera's autofocus mechanism uses a contrast-detection system to determine focus, which may prove difficult when focusing on low-contrast or moving subjects. For very difficult subjects, the Pro90 offers two methods to manually lock focus. The first is to place the part of the subject you wish to emphasize in the center of the frame, and then press the shutter button halfway to lock focus (this also locks exposure in any automatic shooting mode). While holding the shutter button down halfway, recompose the image and fire the shutter. The second method follows the same procedure, only this time you press the Manual Focus (MF) button on the side of the camera while depressing the shutter button halfway. Once the MF icon appears in the LCD display, you can let go of the shutter button, recompose the shot, then make the exposure.

Holding down the MF button pulls up the manual focus distance scale on the LCD screen, and the up and down arrow buttons control the amount of focus. A second press of the MF button returns the camera to autofocus mode. The only drawback here is that the LCD distance scale doesn't report the actual distances. A chart in the instruction manual shows the approximate distances, which would be much more helpful on the LCD screen, especially in low-light situations when distance is a better gauge of focus. In addition to standard automatic and manual focus modes, the Pro90 also offers a Pan Focus mode via the Mode dial. Pan Focus fixes the focus to capture subjects anywhere from 23.6 inches (60cm) away to infinity, eliminating the time required to determine focus for each shot.

The Digital Zoom function, which is activated through the Record menu, increases the camera's telephoto range to 20x or 40x. Digital zoom differs from optical zoom in that it enlarges the center portion of the CCD image digitally, rather than magnifying the overall image with a lens. The results is lower resolution and higher noise levels. A shortcut to activating the Digital Zoom is to hold down the Set button while turning the lens zoom ring to the maximum telephoto position. This engages the 2x digital zoom, and a second turn activates the 4x digital zoom. To cancel the digital zoom, you simply hold down the Set button and turn the zoom ring twice in the wide-angle direction. (Digital Zoom is not available in Stitch Assist and Movie modes, and when the file format is set to RAW.)

Because of its 10x optical zoom range, and the length of the lens barrel, the Pro90 features an Image Stabilizer system, activated by a switch on the side of the lens. When shooting images with the lens at the full 10x telephoto setting, the potential for motion blur, due to camera shake, increases. The built-in image stabilizer also helps with low-light shooting situations and occasionally with slow shutter speeds (for night scenes with very slow shutter speeds, a tripod is recommended for the most steady shot). In practice, Canon's IS technology is enormously useful, making the 10x telephoto much more useful for routine handheld shooting. (We'd go so far as to say that a 10x lens without optical stabilization would be of very limited usefulness.)

The Pro90 lens also features 58mm filter threads to accommodate Canon's series of wide-angle and telephoto lens kit accessories. Our evaluation model was accompanied by the accessory lens hood, which blocks out stray light that might otherwise cause lens flare.