Nikon CoolPix 5700Nikon expands their 5 megapixel offerings, with a long zoom, a new body, but the same legendary Nikon feature set!<<Design :(Previous) | (Next): Optics>> Page 4:ViewfinderReview First Posted: 5/29/2002 |
Viewfinder
A new feature on the Coolpix 5700 is the electronic viewfinder
(EVF), essentially a miniaturized version of the LCD monitor, complete with
information and menu screens. The Monitor Select button on the right side
of the viewfinder switches the view back and forth between the EVF and LCD
monitor displays. Though you can call up the LCD menus in the EVF display,
I found it rather tedious to actually make menu selections that way. It's
much easier to use the larger display of the LCD monitor for menu navigation.
Still, the EVF's informative display reports exposure settings, camera mode
settings, and battery information, all of which are useful during normal operation.
A diopter adjustment dial, tucked on the left side of the eyepiece, adjusts
the view to accommodate eyeglass wearers. Through the Setup menu, you can
specify whether the EVF or LCD monitor automatically activates by default
at camera startup.
The 1.8-inch, 110,000-dot, low-temperature polysilicon TFT LCD monitor features a swivel design. The LCD monitor actually lifts up off of the back panel, flipping out toward the left side of the camera. Once opened, the LCD monitor can swivel around to face up or down over about a 270 degree range of rotation. You can also turn the LCD monitor around to face the camera and then close it to protect the monitor from any accidental scratches. I really like swiveling LCD designs, as they greatly increase the camera's shooting flexibility, allowing you to hold the camera at a variety of angles and still clearly see the LCD display. (They're particularly handy for over-the-head shots in crowds, or for ground-level macro shooting.)
A nice touch in the Coolpix 5700's LCD viewfinder implementation is that you can adjust not only the viewfinder brightness, but its color (hue) as well. A menu option lets you adjust the viewfinder color towards either the blue or the red ends of the spectrum, to help match the viewfinder display to the actual color balance of your captured images. I applaud this, but note that having control only over blue/red tints is only a partial solution. (Technically, you need separate controls for red, green, and blue, in order to be able to completely control the display color. You could get away with only varying two of these relative to the third, but I suspect that full control would result in a bewildering user interface. Still, I'd like to see some attempt to offer more complete color adjustment. Big kudos to Nikon for providing any sort of LCD hue adjustment though.)
The
Coolpix 5700 again features Nikon's powerful zone-based autofocus system. The
camera automatically chooses between five different autofocus zones, or you
can lock it in on any one of them manually. Either way, the viewfinder displays
all five zones, and highlights the currently active one in red. Very slick!
A
Quick Review function lets you quickly check the last exposure while still in
record mode, simply by pressing the Quick Review button above the LCD screen.
This isn't an uncommon feature on digicams, but what's absolutely unique on
the Coolpix cameras is the "picture in picture" review mode (shown
here), which opens a playback window in the upper left-hand corner of the display
screen, while keeping the viewfinder image live on the remaining LCD area. Note
too, that this image isn't restricted to the most recently captured photo. You
can scroll through all the images on the memory card by pressing the rocker
button arrows. The first press of the Quick Review button activates the picture
in picture review mode, a second press enables full-screen playback, and a third
press returns you to full capture mode. At any point, pressing the Shutter button
returns you to capture mode and snaps a picture. Cool!
In
Playback mode, the LCD offers a wealth of information via several display pages.
In total, no fewer than five information screens are available, accessed by
turning the Command dial. The first display is the standard Playback information
readout, which reports the date and time of the shot, file name, quality setting,
and the image number on the card. The next two screens report a long listing
of camera and exposure settings, including the firmware version, focal length,
shutter speed, ISO, etc. A fourth information page shows a histogram view of
the image, illustrating the distribution of brightness values in the image,
with the left edge corresponding to pure black, and the right edge to pure white.
Once you learn how to read it, a histogram is very useful in determining whether
you've managed to capture a good exposure or not. Ideally, a well-exposed image
would produce a histogram curve that just filled the graph from left to right,
indicating that it contained a full range of tonal values. The final information
screen shows lens, shutter, and focus settings, and indicates (by the red brackets)
what the autofocus system had locked onto when the picture was taken. Histogram
displays won't always show you if only a small portion of your image is blown-out:
To address this need, the 5700 blinks those parts of the image that are overexposed,
letting you see exactly where you're losing highlight detail. Very nice,
I'd like to see more manufacturers adopt this feature!
Also
in Playback mode, the LCD offers a thumbnail index display, showing either four
or nine images to a page depending on the setting. The Zoom Rocker button controls
the index display, as the wide-angle side of the zoom lever increases the number
of thumbnails displayed (from one to four to nine). The telephoto side returns
to the single image display, and also activates the playback zoom, which enlarges
the displayed image up to 6x. When you're zoomed in on an image, you can pan
around the image with the rocker control.
Why I don't like EVFs
I guess this is where I need to express my concerns over EVFs in general, and the one on the 5700 in particular. When it comes to cameras with long-ratio zoom lenses, EVFs prove to be a necessary evil. There's just no way to manufacture an optical viewfinder with a long zoom ratio that'll accurately track the field of view of the lens and have acceptable optical characteristics (brightness, distortion, etc) for an affordable price. As a result, once you get over about a 4x zoom ratio, you pretty much have to go with an EVF.
So what's wrong with an EVF, and why do I call it a "necessary evil?" The problem really comes down to light sensitivity. In order to provide a "live" display, the LCD inside the EVF has to be refreshed quite rapidly, certainly no less than 5 times per second or so. This places a severe limit on the amount of light the CCD can gather for each refresh. (If the refresh rate were 5 times per second, the maximum shutter time for each frame would obviously be about 1/5 of a second.) While you can generally tolerate a darker image in the viewfinder than you'd accept in the final photograph, the fact remains that EVF-equipped cameras can almost always capture acceptable photos under much lower light levels than those at which you can actually see anything through the viewfinder. There are tricks the camera engineers can play to help this situation somewhat, but they're limited. Slowing refresh rates in dim lighting is the first trick to use, and that's what the Nikon designers did with the 5700. The 5700's refresh rate gets much slower in dim lighting conditions. Another trick is to crank up the signal amplification between the CCD and LCD, to get a brighter image. You'll get more image noise on the LCD, but most users will accept pretty noisy EVF images if the increased noise at least lets them see their subjects. Nikon appears to have adopted this latter practice as well, but only to a degree.
In playing with the 5700's EVF, I found that it responded pretty directly to the camera's ISO setting: Higher ISOs produced brighter EVF displays under darker conditions. I discovered though, that changes in EVF sensitivity lagged changes in the ISO setting by a few seconds.The viewfinder display was at least somewhat usable down to surprisingly low light levels with the ISO set to 800, but it took a good 6-10 seconds for the display to brighten after changing from a lower ISO setting. If want to shoot at lower ISO settings to minimize image noise (and are patient enough), it's possible to set the ISO up to 800 to frame your shot, then dial it back down to whatever value you want to shoot at. This is feasible, but far from convenient. (Here's a suggestion to the Nikon engineers: How about a firmware option that would boost the effective ISO dramatically only for the viewfinder display? A menu option could turn this on or off, preserving the relationship between viewfinder brightness and ultimate exposure level for normal shooting.) Overall, the EVF in the 5700 does a somewhat better than average job of letting you see under dim lighting, but it's still no match for a true optical viewfinder when it comes to low light shooting.
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