Viewfinder (3.5)
As part of the Canon A-series and to keep with tradition, the A640 has an optical viewfinder. The viewfinder seems to be more of a convention than an actual functional component. The viewfinder provides only a vague resemblance of the captured image. The optical viewfinder zooms just as the lens does, but it certainly doesn’t provide the same view. There are blurry spots around the view, especially around the edges of the frame. The view is horribly inaccurate too. When the viewfinder is zoomed out to its widest (which isn’t very wide at all), the finished image captures more around each edge, and this is the optical viewfinder at its best. When the viewfinder is zoomed in, it cut off about a third of the captured image at the bottom. This is even worse in the macro mode. Photographers who insist on using the optical viewfinder should use the viewfinder only when zoomed out on subjects. Zooming in causes the viewfinder to be terribly inaccurate and makes it impossible to frame subjects properly.
LCD Screen (6.0)
The A640’s LCD monitor is among the largest on the Canon A-series digital cameras. This model’s predecessor, the A620, has a 2-inch LCD that folds out and rotates. While both cameras have folding and rotating LCD monitors, the screens are very different. The Canon A640’s larger 2.5-inch low-temperature polycrystalline silicon LCD screen has a much wider viewing angle. The A620’s screen solarized unless viewed straight on, requiring users to constantly twist and turn the monitor. The newer A640 won’t require as much fussing because the screen can be seen from above, below, and side to side. Images have good contrast and do well even in bright direct light, and that is good because the A640 doesn’t have a brightness adjustment like many other compact digital cameras do. The A620 and A640 both have 115,000 pixels of resolution on their LCD screens, but the limited resolution is spread even thinner on the PowerShot A640. This poor resolution makes manual focusing very difficult, but it is still a better option than the optical viewfinder since it has 100 percent accuracy in its framing. The LCD screen can be turned off or the display info changed from basic to full with the “Disp.” button. In the setup menu, users can also add grid lines and/or 3:2 guide lines to really clutter the screen. The Canon A640’s LCD screen has disappointingly low resolution, but its wide view and flexible nature still make it a usable component.
Flash (6.5)
The Canon PowerShot A640 has a built-in flash unit that is fixed to the front of the camera. It sits above the lens in the top right corner of the front. This makes it especially vulnerable to wandering fingertips and will produce a hard-edged shadow to the side of the subject. I snapped at least a few pictures that were half-bright because my left fingers had nowhere to go but in the way of the flash unit. When the top of the navigational control is pushed, only a few flash modes appear: On, Off, and Auto. This isn’t where the options end, though. There are a lot more in the menu system. The shooting menu lets users activate red-eye reduction and slow sync. It also lets users choose whether to fire the flash before the shutter opens or as it opens (1st or 2nd curtain options available in the shooting menu).
The flash is fairly powerful considering that it isn’t a unit that pops up and is relatively small (though also fairly unflattering for the same reasons). It lights up subjects from 1.5-14 ft when the lens is zoomed out and to 10 ft when zoomed in. The flash is also somewhat functional in the macro mode, where it lights from 9.8 inches to 1.5 ft. The flash’s light is nearly centered, but it doesn’t cover the entire frame very evenly. The edges definitely lack the light that reaches the middle. The flash’s power can be adjusted within the Func./Set menu to +/- 2 in 1/3 increments. This is a nice touch for close-ups and portraits when the flash tends to overdo it. Users who find that this flash range won’t cut it for their needs will want to purchase the optional Canon HF-DC1 slave flash that can extend the range to about 30 ft. It costs about a hundred dollars and automatically syncs with the built-in flash unit.
Overall, the Canon PowerShot A640’s flash is very functional, but it will likely need some tweaking with the flash compensation and mode to get the job done right.
Zoom Lens (7.0)
A 4x optical zoom lens extends from the front of the camera body with its 7.3-29.2mm measurements. This is equivalent to 35-140mm in the common 35mm format and is longer than the standard compact 3x lens. Users can add even more zoom power with conversion lenses that attach to a threading when the outer rim is removed (via the button to the bottom right of the lens). If users want to pretend they have a tele-converter, there is a digital one available via the recording menu. It is found in the Digital Zoom sub-menu with Standard (4x), 1.4x and 2.3x options on hand. According to Canon’s August 24 press release that introduced the A640, this function “digitally emulates having a traditional tele-converter attached.”
The Canon lens has some barrel distortion that shows up at its widest focal length and in macro shooting. It simply bends lines but not as dramatically as with a fish-eye lens. The A640’s lens has maximum apertures of f/2.8 at the 35mm focal length and f/4.1 at the 140mm focal length. This should allow sufficient natural light onto the image sensor, so users won’t have to boost the ISO or lengthen the shutter speed – both of which would increase the amount of noise in the final image. The lens is controlled by a zoom ring that surrounds the shutter release button. The control is large enough that is doesn’t completely cramp the hand to move and is a step up from some PowerShot models. When the lens itself moves, though, it makes quite a sound. It isn’t the chirping bird or a trapped moth sound like on some digital cameras, but it is a loud electronic noise – something that could be used as a special effect on a Hollywood set for an incoming UFO. Overall, the 4x optical zoom lens has a nice range and lots of flexibility with threading and optional conversion lenses.
