Nikon D70SNikon updates its midrange SLR with improved focusing, larger LCD, a new menu interface, and more.<<Design :(Previous) | (Next): Optics>> Page 6:ViewfinderReview First Posted: 06/30/2005 |
Viewfinder
Like all SLRs, by definition the D70S has an optical viewfinder that receives light through the same lens that will direct light to the imager when the mirror flips up and the shutter opens. Rangefinder-style cameras have separate optics for viewfinder and imager, so the image can be slightly off due to what's called parallax error. This is largely eliminated as a problem with LCD viewfinders on consumer-grade digital cameras, but delay can be increased because the LCD usually lags behind reality at least a little bit (not to mention that LCD displays are notoriously power-hungry!). An SLR design allows the user to see the very view that the camera will see at the speed of light, eliminating some of the lag factor. An illuminated display inside the viewfinder provides detailed camera and exposure information, including focus area indicators, focus confirmation, focus mode, shutter speed, aperture, metering, AE/FV lock, battery status, exposure and flash compensation, frame counter, and flash ready light. When activated through the menu, the view also includes an alignment grid, useful for lining up difficult shots. That this can be turned on and off indicates that an LCD-equipped mirror is employed in the Pentamirror arrangement (we're seeing lower cost SLRs sporting Pentamirrors rather than Pentaprisms. This is also true in Canon's Digital Rebel. Pentamirror finders are supposed to be less bright than Pentaprisms, but I haven't found any huge disadvantage among the cameras I've reviewed. A Pentaprism is a solid piece of crystal or glass that is more expensive than a set of mirrors, and that also adds weight to the camera body.)
The LCD panel is not usable as a viewfinder on digital SLRs, for the simple reason that the mirror is directing light to the optical viewfinder, completely obscuring the digital sensor until the time of exposure. It can, however, provide a good deal of information after an image has been captured, demonstrated well in the D70S design. No fewer than five different display screens are available, ranging from no information other than the 130,000 pixel picture, to very detailed lists of the settings, plus a histogram, and an overexposure alert. The histogram is a graph of how many pixels in the image have each brightness level. The brightness is the horizontal axis, running from black on the left to white on the right. The height of the graph shows the number of pixels at that brightness level. This kind of display can be very helpful in determining over- or underexposure. An evenly-exposed, low-contrast subject would create a histogram that stretches across the entire width of the display, using the full range of brightness values available. An underexposed image will have a histogram with all the data lumped on the left of the histogram, and an overexposed image would be bunched up on the right.
Another display mode that's useful is the Highlights display, which flashes any overexposed areas, alternating white and black. Few objects should appear as pure white in a well-exposed photograph, because few objects in the real world are pure, saturated white to our eyes. Obvious exceptions are light sources, like lamps and the sun. The flashing Highlights display is thus very useful for seeing any parts of the image that might be overexposed. It's particularly helpful when only isolated highlight areas are overexposed. Because the histogram display shows the distribution of all the pixels in the image, small overexposed areas don't produce a noticeable blip on the graph, making them easy to miss. The Highlights display takes care of that, by calling attention to overexposed regions very directly.
Though it's buried in the control buttons, the D70S has the ability to zoom in on photos up to 4.7x (an apparent slight increase in magnification relative to the 4x of the previous model) to examine focus and detailed framing in playback mode. The animated series of shots shows how this works. As you enter a zoomed playback mode, the display changes from a 3:2 ratio view, which shows the entire image, to a 4:3 ratio, matching the dimensions of the LCD. Once you've entered zoomed playback mode, pressing the Thumbnail display button (of all things) while rotating the Main control dial zooms in on the image. Once zoomed, you can use the Four-way rocker to move around inside the image. Pressing the Thumbnail display button toggles to a display showing the position for your zoomed window within the normal-sized image, indicated by a bold red outline. You can move this window around with the Rocker Pad control, and then pop back into the zoomed view by releasing the Thumbnail button again. This may all sound a little complicated, and it is, but after very little acclimation, I found I could move around within the enlarged display very fluidly using this arrangement. See the animated screen shot above for a whirlwind tour of the feature. Pressing Playback Zoom/Quality/Enter button zooms you in and out by 2x, and you can move around with the navigator button.
There is one really bizarre aspect to the D70S's display though, that was actually present in the D70 as well, but that I simply missed commenting on. (Actually, it was IR News Editor Mike Tomkins who first noticed this one.) With the "Rotate Tall" option enabled on the playback menu, vertical, "portrait-format" images are displayed on the rear-panel LCD oriented vertically. That's all well and good. The weirdness comes when you zoom in on a vertical-format image, and the zoomed image is confined to the same tiny area of the LCD that the full-sized portrait-format image was in! Whaat?!? Why can't the image expand to fill the full LCD screen as you zoom into it. Having noticed this, we then realized that the same thing happens with landscape-oriented images: The LCD screen has a 4:3 aspect ratio, but when you zoom into landscape-formatted images, only a 3:2 ratio area is actually used to display the zoomed image. Bottom line, you don't get to see as much of the image at once, and so have to scroll around more to see all of it. In fairness, I don't know how many other d-SLRs do this, but the Canon Rebel XT that I checked just now definitely makes use of all the available LCD area when zooming in on images in playback mode, regardless of their orientation.
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