Canon PowerShot S40A new shape, sleek design, direct support for a Canon inkjet printer, and four megapixels of resolution!<<Optics :(Previous) | (Next): Shutter Lag & Cycle Time Tests>> Page 6:Exposure & FlashReview First Posted: 10/1/2001 |
Exposure
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Shutter Priority mode puts you in control of the shutter speed setting (from 1/1,500 to 15 seconds), while the camera chooses a corresponding lens aperture. As with the Program AE mode, you maintain control over all other exposure options. Aperture Priority works along similar lines, except that you control the aperture (f/2.8 to f/8.0) and the camera chooses the best corresponding shutter speed. Both the shutter speed and aperture values are displayed on the LCD monitor. If the camera doesn't agree with the exposure settings you've selected, the LCD indicators will turn red, letting you know that either the aperture or shutter speed needs to be corrected.
A number of preset "scene" exposure modes are also available for shooting under special conditions. These modes preset a variety of camera options, letting complete novices get decent pictures in challenging situations without having to know all the ins and outs of the camera. Portrait mode uses a large aperture setting to reduce depth of field, resulting in blurred backgrounds and strong focal emphasis on the primary subject. Landscape mode uses a small aperture to keep both the foreground and background in sharp focus. A slow shutter speed is also common in Landscape mode, so it's recommended that you use a tripod.
Night Scene mode uses a slow shutter speed to capture the color and detail of any evening setting, along with a flash exposure to illuminate the primary subject in the foreground. When slow shutter speed and flash are used together, the overall scene is more evenly exposed. This mode can also be combined with the redeye reduction flash for portraits, or the flash can be turned off. Portrait subjects should be warned to stay still after the flash, until the shutter is closed.
Fast Shutter is provided for fast-moving subjects such as sporting events, and Slow Shutter is available for creating a sense of motion in fast-moving subjects. Fast shutter speeds stop action to maintain sharp focus on moving subjects, while slow shutter speeds tend to blur the subject because the shutter stays open longer to record the image. This last effect is particularly striking when used with swiftly moving water such as that found in water falls or streams.
Color Effects has been moved from the Record menu to the Mode dial on the PowerShot S40. The Color Effects setting provides a choice of four color options along the bottom of the LCD display, which are selected using the left and right arrow keys. These choices include Vivid color, Neutral color, Sepia tone, or Black-and-White. Effects are shown on the monitor so you can view the image before it taking the exposure..
A quick-review mode lets you quickly confirm the most recently recorded image. To access the Review mode, you simply push the Replay button under the Mode dial to the right to automatically switch to image playback. If you like, you can immediately erase the displayed image by pressing the Manual Focus / Delete button, which pulls up a small erase menu on the bottom of the monitor. A dialog appears on-screen, with the "Erase?" button highlighted. Press the "set" button on the Multicontroller to erase, or the right arrow and then the set button to return to normal playback. To return to Shooting mode, press the Replay button to the right a second time, or simply touch the shutter button.
Exposure compensation can be adjusted from –2 to +2 exposure values (EV), in one-third-step increments. The camera's metering system offers three operating modes -- Evaluative Light Metering, Center-Weighted Averaging, and Spot AE Point -- which are selected by pressing the Metering / Microphone button on the left side of the LCD monitor. Evaluative metering divides the image into several zones and determines the exposure based on the position of the subject, image brightness, ambient light, direct light, and backlighting. Center-weighted averaging is based on an averaged light reading of the overall scene, but places more emphasis on the center of the viewfinder or LCD monitor. Spot metering reads only a specific point in the viewfinder. Through the Record menu, you can choose a Center point to take the reading, or one of two additional AF Points corresponding to the AF Focus frames on either side of the center point.
Another high-end feature brought over from Canon's G2 is independent exposure lock. With most digicams, you can lock both focus and exposure by half-pressing and holding the shutter button prior to the shot itself. This can be very handy for off-center subjects. Sometimes though, you want to lock the focus on one part of the subject, but set the exposure based on a different part. On the S40, this is accomplished by half-pressing the shutter button (which will set both focus and exposure), and then subsequently pressing the sound/metering button at bottom left, to reset the exposure. Of particular note, this option also works for flash exposures, whenever the flash is enabled. Very slick.
The S40 offers seven White Balance modes, including Auto, Daylight, Cloudy, Tungsten, Fluorescent, Fluorescent H (daylight), Flash, and Custom. The Custom mode allows you to manually set the white balance by holding a white card in front of the camera and pressing the Metering / Audio button to set the value. ISO film speed equivalents are set in the Record menu, with a choice of Auto, 50, 100, 200, 400 ISO values. The higher the ISO setting, the more you can extend the camera's exposure range in low-light situations. Just keep in mind that higher ISO values have slightly lower quality levels, with increased image noise. Other manual exposure adjustments in the Record menu include: Image Contrast, Sharpness, and Saturation. These give you a little more creative control over your image processing.
Flash
The S40's built-in flash operates in one of five modes: Auto, Red-Eye Reduction (Auto), Red-Eye Reduction (Flash On), Flash On, and Flash Off. The Auto mode enables the camera to determine when flash is necessary, based on existing exposure conditions. Flash On means that the flash fires with every exposure, regardless of lighting conditions, and Flash Off completely disables the flash. The two redeye reduction modes fire a small pre-flash before the full flash, to reduce the dreaded redeye effect in portraits. The difference between the two redeye modes is that the auto mode puts the camera in charge of when to use the flash, while the Flash On mode fires the flash with every exposure. All flash modes are accessed by pressing the Flash / Index button to the left of the optical viewfinder.
The flash exposure can be adjusted from -2 to +2 EV in one-third-step increments by the using the four-function Exposure Compensation button on the camera's back panel. (Depressing the button four times cycles to the Flash Compensation adjustment.) As mentioned earlier, you can also lock the Flash Exposure (FE) setting for a specific area of your subject, just as you would with a normal exposure. Simply center the portion of the subject you want to have metered and half-press the shutter button. Then, while still holding the shutter button down, press the Metering / Audio button to lock the flash exposure (an asterisk will appear at the bottom of the screen). The flash will fire a pre-flash to lock the exposure reading, then you can recompose your image and make the exposure with the FE lock in place. (Note: Pressing any other button after the Metering / Audio button will cancel the flash exposure lock.)
Canon rates the S40's flash effectiveness from 2.7 to 14.1 feet (0.8 to 4.3 meters) at maximum wide-angle and 2.7 - 8.2 feet (0.8 to 8.2 meters) at maximum telephoto. As our first evaluation unit was a prototype model, we did not test the flash range, but we did note that the flash significantly overexposed close-up images.
Auto Exposure Bracketing
The Auto Exposure Bracketing (AEB) mode is the third function controlled by the EV button on the camera's back panel. It automatically captures a series of three images, each at a different exposure setting. You can manually set the exposure variables in one-third-step increments, from -2 to +2 EV, by depressing the EV button three times to activate the mode and using the arrow buttons to choose the amount of variation between photos. 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. This function cannot be used with flash photography. If the flash fires, only one image will be recorded.
Continuous Shooting
The S40 has two Continuous Shooting modes, which are accessed through the Drive sub-menu of the Record menu. Standard Continuous Shooting captures multiple, successive still images, at about 2.5 frames per second, providing enough time to display each image briefly after it is captured. High Speed Continuous Shooting captures images at 1.5 frames per second, as long as you hold down the shutter release. (The number of images and actual shot-to-shot speed depend on several factors, including the amount of memory remaining on the flash card.)
Movie Mode
The S40 also offers a Movie mode, which is accessed by turning the Mode dial on top of the camera to the miniature movie camera symbol (a camera will appear in the upper left corner of the LCD display). The AVI / Motion JPEG files are recorded at 320 x 240 or 160 x 120 pixels, at approximately 15 frames per second. Recording time is 30 seconds at the 320 x 240 resolution and 120 seconds at 160 x 120 resolution,, depending on the amount of memory available on the CompactFlash card. To begin recording, you simply press the shutter button all the way down and hold it there until the red circle in the upper right corner of the LCD appears. To end the recording, press the Shutter button again. The flashing green LED light next to the eye-level viewfinder indicates that the camera is storing the movie. When finished, you can view the recording by pushing the Replay button to the right and depressing the Set button. The camera will play back both moving images and sound. (Note that the recording options are largely preset in Movie mode: Image resolution, Self-Timer, Exposure Compensation, White Balance, and Macro and Manual focus are the only adjustable functions.)
Stitch-Assist Mode
The Stitch-Assist mode records a series of overlapping images to create horizontal or vertical panoramas, and 2 x 2-frame rectangular composites. A framing guideline for each format appears in the LCD monitor to help line up successive shots. For the panoramas, you can take as many images in a series as you want, enabling you to record a full 360-degree circle of the surrounding scenery. The 2 x 2 mode uses a series of only four images, starting from the top left corner and moving in a clockwise direction, to create a complete composite. You can then use Canon's PhotoStitch program to seamlessly combine the images in your computer.
Self-Timer Mode
The Self-Timer is set through the Drive sub-menu in the Record menu. When set to Self-Timer, the camera displays the standard self-timer icon (a clock counting down) in the LCD display, and depressing the Shutter button activates a 10-second or 2-second countdown (depending on the Drive mode selected), during which a bright blue lamp on the camera's front panel blinks, gaining speed in the last two seconds. If the camera's Beep function is turned on in the Setup menu, you will also hear the beep counting down.
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