Olympus E-20Olympus updates their bargain-priced Pro SLR with a 5 megapixel sensor and improved electronics<<Design :(Previous) | (Next): Optics>> Page 4:ViewfinderReview First Posted: 11/28/2001 |
Viewfinder
For composing images, the E-20 features an SLR (Single Lens Reflex) optical viewfinder and an LCD monitor. The optical viewfinder's SLR design utilizes a "beam splitter" method rather than the traditional mirror design. Oddly, although the image is carried to the CCD and viewfinder simultaneously, there's still a brief "blackout" each time the shutter trips. I'm not sure why this is, since the optical path looks as though it should support light going to the viewfinder and CCD at the same time. One benefit though, is that the beam splitter design should reduce vibration significantly for shooting under dim lighting conditions with long telephoto lenses, since there's no mirror slamming up as the exposure begins. Another benefit is that, with no mirror to flip up, the maximum cycle time can be very fast. (Some very high-end film-based SLRs have what are called "pellicle" mirrors, which are partially transmissive, and remain in place as the shutter opens. This approach is usually adopted in order to achieve very high frame rates of 10-frames-per-second or so though, quite a bit beyond the 2.5-frame-per-second capability of the E-20.) The illustration below shows the optical path through the camera: The beam-splitter is the squarish unit at the rear of the camera, where one light path branches off vertically to go to the eyepiece, and the other proceeds straight through to the CCD.
While the beam-splitter approach does have the advantages described above, there is a tradeoff in light sensitivity associated with it: Since some portion of the light must be sent through the viewfinder, there will be that much less reaching the CCD. If the light were split evenly between the two, this would be a one f-stop loss in ISO. That said, I was impressed with the E-20's low light performance, among the best I've seen among cameras I've tested, regardless of price.
Inside the optical viewfinder are central autofocus target marks and an LED display that reports shutter speed, aperture, flash, metering system, exposure compensation, and whether or not the image is in focus (indicated by a full circle that lights solid when focus is set). A soft, rubber bezel around the outside of the eyepiece comfortably cushions the eye, and a notched, dioptric adjustment dial (also around the outside of the eyepiece) adjusts the focus in the viewfinder to accommodate eyeglass wearers. The notched dioptric dial is a little difficult to turn while looking through the viewfinder. I found it easier to pull the camera away from the face, move the dial a notch, and then look back through the viewfinder to check the view. This is only slightly annoying, as I'd ideally like to be able to look through the viewfinder as we adjust the dioptric dial. I did appreciate that the dioptric adjustment had very definite click-stops in its rotation though, so it isn't likely to get jostled out of adjustment inadvertently. It also seemed to offer a wider range of adjustment than I'm accustomed to seeing, but I don't have any quantitative measure to support that conclusion. As with most SLRs, light entering the rear viewfinder element can affect exposure, so the E-20 incorporates a lever-actuated shutter to block off the eyepiece when you're using the camera on a tripod. (That is, whenever your eyeball isn't blocking light from entering the viewfinder eyepiece.)
The 1.8- inch, color, TFT (Thin-Film Transistor) LCD monitor features 114,000 pixels and a tilting design. A small release lever on the left side of the monitor pops the top of the LCD monitor outwards from its compartment, allowing you to tilt the display down by about 20 degrees, useful for times when the camera is slightly overhead. By lifting it off of the back panel slightly, the LCD monitor can also face upwards at a 90-degree angle, handy for low-angle shots. The Display button next to the LCD monitor turns the image display on or off, and the Menu button just below it calls up the LCD menu system for whatever mode the camera is currently in.
Just like the optical viewfinder, the LCD monitor features an information readout at the bottom of the screen, reporting the exposure settings, focus lock, and flash mode. Pressing the Info button repeatedly cycles between two information screens and no information at all. The first information display reports the shutter speed, aperture and exposure compensation. The second screen displays a focus range indicator in both meters and feet, reporting the approximate distance between the camera and the subject. The focus indicator is great, both in autofocus mode, when it provides a rangefinder capability, or in manual focus mode, where it would be useful for situations in which you know the distance to the subject. For more detailed information on battery power, the number of available images, and more extensive exposure information, the small status display panel on top of the camera features a more complete information readout. Olympus estimates that the LCD monitor represents about 100 percent frame accuracy, but I found it only showed 90-92 percent of the final frame.
The E-20 offers a fair bit of exposure information during playback, optionally available by pressing the Info button on the rear panel while rotating the Subcommand dial. Three levels of information are available, as shown at right. We liked the control over the amount of information displayed, but would liked to have been able to simply switch the information overlay on or off just by pressing the Info button. (That is, without having to resort to the Subcommand dial.)
The E-20 also offers a histogram function displaying the distribution of brightness throughout the image, although you may have to read the manual (as I did) to find it. To access the histogram function, you have to first put the camera into the PC Connection mode (?!) on the Mode dial and then activate the histogram through the settings menu there. (This settings menu also controls other camera functions, such as the function of the Macro button, date and time setting, file naming scheme, and RAW file format enabling.) Once activated, you can toggle between the normal exposure-information display and the histogram by pressing the Info button. I liked the E-20's histogram display because it was fairly large, and seemed to show good detail in terms of the number of pixels at various brightness levels. It seemed to do a bit better job than other histogram displays we've seen of telling us when a relatively small percentage of the image was blown out, but I also really like camera displays that show blown-out regions as black or blinking, to help see just where you're losing highlights in an image. The E-20's playback display doesn't offer this option however. (Note to Olympus: Any chance of seeing this feature as a firmware upgrade for the E-20?)
The histogram display wasn't "live" in capture mode, but rather I had to first capture a frame, then switch to the "quick review" mode by pressing the display button twice in rapid succession. This actually puts you in Playback mode, in that you have all the normal playback functions available to you. The advantage is that you can switch back to capture mode instantly, just by touching the Shutter button. (The camera will also revert to capture mode automatically if you don't touch any of the controls for 60 seconds or so.)
In Playback mode, the LCD monitor offers a playback zoom function, which enlarges captured images for closer inspection of fine details. It appears to offer magnifications up to about 4x, a very useful level, but I've seen higher magnifications on some competing models, and would prefer more magnification than the 4x offered here. There's also an index display mode, which displays up to sixteen thumbnail images on the screen at one time, perfect for selecting images to protect, delete, or print.
In my testing, I found the E20's viewfinder to be just a little tight, showing about 94 percent frame accuracy at wide angle and about 96 percent at telephoto. As noted above, the corresponding numbers for the LCD finder were 90 and 92 percent.
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