Olympus E-20Olympus updates their bargain-priced Pro SLR with a 5 megapixel sensor and improved electronics<<Optics :(Previous) | (Next): Shutter Lag & Cycle Time Tests>> Page 6:Exposure & FlashReview First Posted: 11/28/2001 |
Exposure
The E-20 offers excellent exposure control, with a range of manual and automatic exposure modes available. Through the Mode dial on top of the camera, you can set the exposure mode to Program, Aperture Priority, Shutter Priority, or Manual. In Program exposure mode, the camera selects both the aperture and shutter speed settings, while you can adjust the exposure compensation, metering mode, ISO, flash, and white balance. Aperture Priority mode allows you to set the lens aperture (from f/2.0-2.4 to f/11.0, depending on the zoom setting) while the camera selects the best corresponding shutter speed. Shutter Priority modes works in the exact opposite, allowing you to set the shutter speed (from 1/18,000 to 60 seconds - see below for a discussion of maximum shutter speeds though) while the camera selects the appropriate lens aperture. In both Aperture and Shutter Priority modes, you have control over the same exposure variables as in Program mode. Shooting in Manual exposure mode gives you control over both the shutter speed and aperture setting, with a Bulb setting for exposure times all the way out to 8 minutes(!). Manual exposure mode also allows you to change all other exposure variables, with the exception that exposure compensation and metering mode aren't available. (Which makes sense, since the camera's metering system isn't involved when you're in full-manual mode.) In both Aperture and Shutter Priority modes, the designated variable is changed by simply turning the Command dial on top of the camera. In Manual mode, aperture is set by turning the small Subcommand dial on the back panel, and shutter speed is changed by turning the main Command dial on the top panel. The camera doesn't offer any preset shooting modes (as do many more consumer-oriented cameras), for shooting in special situations such as night scenes or sunsets. However, the camera's instruction manual provides detailed information and tips for shooting portraits, backlit subjects, action subjects, etc.
Three metering modes are available on the E-20, in all exposure modes other than Manual. Digital ESP Metering reads multiple locations across the entire image area to determine the correct exposure value. Center-Weighted Average Metering reads light in a relatively large area at the center of the subject to determine exposure (the metering area takes up about 11 percent of the total frame area). The third mode, Spot Metering, takes a light reading from the very center of the subject (about 1.6 percent of the viewfinder image area). The metering mode is selected by holding down the Metering button and turning the Command dial (or Subcommand dial) until the desired icon is displayed in the viewfinder. Like metering, exposure compensation is adjustable in all exposure modes except Manual. By pressing the Exposure Compensation button and turning the Command dial (or Subcommand dial), the exposure can be adjusted from -3 to +3 exposure equivalents (EV) in one-third-step increments.
An exposure lock function is controlled by the AE Lock button on the back panel of the camera. To use AE Lock, simply point the center of the viewfinder at the part of the subject you want the exposure based on, press and hold the AE Lock button, reframe the subject, and trigger the shutter. The separate AE Lock button is a nice feature, because it lets you completely recompose your shot (including zoom and focus adjustments) without losing the desired exposure setting.
You can use the AEL and Shutter buttons to effect a focus-lock function. Half-press the Shutter button to lock both exposure and focus. Then center on your exposure target, and press the AEL button. This *re-locks* the exposure, while not affecting the focus. Finally, while still holding down the AEL button (and still half-pressing the Shutter button), reframe your picture and fully press the Shutter button. Not the most straightforward implementation I've seen, but the function is nonetheless there and usable.
White balance on the E-20 offers three operating modes: Auto, Quick Reference, and Preset. The Auto setting selects the whitest portion of the subject and adjusts the color balance to achieve the best white value. The Quick Reference setting is equivalent to a manual white balance mode, in that it allows you to set the white balance by placing a white card in front of the subject to balance the color. You then press the Quick Reference white balance button on the front of the camera to save the setting as a preset value. This saved white value will automatically be used the next time the white balance is set to Quick Reference, unless the value is changed again through the same method. Under the Preset white balance mode, the camera offers a selection of Kelvin temperatures, from 3,000 to 7,500 degrees, to match a variety of light sources. The instruction manual provides a detailed chart reporting the temperature setting and the lighting situation it's intended for. While I'm a big fan of the sort of fine-grained white balance control provided by the color temperature preset option, I'd really like to see the range extend below 3000K. - Household incandescent lighting of the type almost universally used in the US generally has color temperatures in the range of 2400-2800K, so even the 3000K setting doesn't go far enough. (Although the Quick Reference option has no trouble dealing with light sources as warm-hued as this.)
Image sharpness can be adjusted to Hard, Soft, or Normal on the E-20, through the Record menu. These affect the amount of in-camera sharpening applied to the images, although the three options operate across a fairly narrow range. "Soft" still seems to leave some sharpening applied, while "Hard" is a relatively modest boost over the Normal setting.
Progressive vs Interlaced Scan.
I wasn't sure just where to put this part of the discussion, as it isn't normally part of a still camera review. - Here in the "Exposure" section seems to make the most sense, so here it is:
The E-20N supports two exposure modes, Interlaced and Progressive. It appears that the camera's normal operating mode involves clocking data off the CCD array in two chunks, corresponding to the even- and odd-numbered lines of the CCD. This results in a maximum shutter speed of 1/640 of a second, governed by the camera's mechanical shutter. (Not terribly fast, and one of the principle limitations of the original E-10 model.) If you need higher shutter speeds, you can optionally put the camera into Progressive Scan mode, in which it only uses every other row of sensor elements, dropping vertical resolution in half. The benefit though, is that the camera can then cycle the CCD itself to effect an electronic shutter, with minimum shutter time of only 1/18,000 of a second. That's *fast*!
I was very surprised to find mention of interlaced scan on a high-end digital still camera, as interlaced scan is a principle cause of distortion and artifacts when shooting rapidly-moving subjects with video cameras. It appears that what's happening in the E-20 isn't so much that the image is being built up by successive scans of the CCD, but that the information captured is read out in successive cycles after it has been captured. Thus, no moving-subject distortion, only a limitation on maximum shutter speed, since the CCD can't be electronically gated in this mode.
Regardless of the specifics of its implementation, the E-20's progressive scan option lets you trade off half of your vertical resolution in order to achieve very brief exposure times.
Flash
The E-20 features a built-in, pop-up flash with five operating modes, including Automatic, Redeye Reduction, and Fill-In. Flash mode is controlled by pressing the Flash button and turning either the main Command dial or the Subcommand dial. The Automatic flash mode places the camera in charge of when to fire the flash, based on the existing light level and exposure. In Redeye Reduction mode, the flash fires a rapid burst of 10 short flashes to contract the pupils of the subject's eyes before the main flash fires. The Fill-in flash mode fires the flash with every exposure, regardless of the light level. Finally, the flash can be completely disabled by returning it to its compartment. The built-in flash intensity level can be adjusted through the record menu, from -2 to +2 EV in one-third-step increments.
Olympus estimates the built-in flash as effective from 0.6 to 18.3 feet (0.2 to 5.6 meters), at the normal intensity and ISO 100 settings with the lens set to its wide angle focal length, or 0.6 to 12.5 feet (0.2 to 3.8 meters) with the lens at telephoto. This agreed well with my own testing, which showed constant brightness to 12 feet with the lens in its telephoto position, and then gradual dimming after that point.
A hot shoe on top of the camera accommodates an external flash, as does the PC sync terminal on the side of the camera. You can use the internal flash and an external flash together, as the camera automatically sets the internal flash to Automatic if popped up when the external flash is connected. Flash intensity level can also be controlled through the camera for a dedicated external flash, via the same method as for the internal unit. Olympus offers the FL-40 external flash as an accessory, and the instruction manual contains detailed instructions for connecting the flash and setting it up. (Note that the flash exposure adjustment option likely will not be available with third-party accessory flash units, as it requires extra connections on the flash shoe to implement this function.)
In the E-20's manual, Olympus notes that the flash "may not be effective" at shutter speeds higher than 1/250, although it isn't clear whether that's due to issues with sync timing, or the duration of the flash itself. - Testing the E-20N with my White Lightning studio strobe (UltraZap 800 model), I found I could get perfectly good flash exposures out to shutter speeds of 1/4000 of a second.
Auto Bracketing
In all exposure modes except for Manual, an auto bracketing feature takes three exposures of the same image at different exposure values (one at the set exposure value, one overexposed, and one underexposed). Through the record settings menu, you can set the EV increment you want each image to differ by, with options of one-third, two-thirds, or one EV step in either direction. The camera's internal flash must be closed for auto bracketing to work, and the self-timer is unavailable when this feature is enabled.
Sequence Mode
The Drive button on the side of the camera accesses the Sequence shooting mode, which allows you to capture up to four successive shots at roughly 2.5 frames per second with one press of the Shutter button.
Self-Timer and Remote Control Photography
Also through the Drive button, the E-20 offers the Self-Timer and Remote Control shooting modes. The Self-Timer features a 12-second countdown before the shutter is fired, allowing you to get into the image after pressing the Shutter button. As with normal exposures, the camera sets focus with the half-press of the Shutter button, meaning that you shouldn't stand in front of the camera to start the countdown and press the Shutter button.
The E-20 works with an included infrared remote control as well as an accessory wired remote control unit. The Remote Control shooting mode, accessed through the Drive button, sets the camera to receive signals from the infrared remote control unit, which works as far as 16.6 feet (5m) from the camera's front.
The wired remote control unit can be used in any capture mode and doesn't require you to set the Drive setting to Remote Control mode. Instead, when the remote control wire is connected to the camera via the side terminal, the remote functions are instantly available. With the wired remote, you can halfway press the shutter button to set focus, a function that the infrared remote doesn't allow. The wired remote is perfect for shooting with the Bulb shutter setting or any slow shutter speed, to reduce any camera movement caused by pressing the shutter button.
Time-lapse Photography
Through the Record menu, the E-20 offers a Time-lapse Photography mode. You can set the shutter intervals from 30 seconds up to 24 hours, and the camera will continue to take pictures at the set interval until the batteries die, the memory card fills up, or the camera is turned off.
Low Light Photography
I don't normally have a separate section in my reviews on a camera's low light capability, but the E-10 was so exceptional in this respect that I thought it warranted separate coverage. The E-20 appears pretty impressive in this respect as well, but we didn't receive a wired remote with our test unit. I've asked Olympus for one so I can shoot some really long exposures on the tripod, and will try to come back here (time permitting) to fill-in with some shots of the sort I took by moonlight with the E-10. - See the E-10 review for some impressive examples of shots taken by moonlight with that camera.
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