Nikon CoolPix 5700Nikon expands their 5 megapixel offerings, with a long zoom, a new body, but the same legendary Nikon feature set!<<Viewfinder :(Previous) | (Next): Exposure & Flash>> Page 5:OpticsReview First Posted: 5/29/2002 |
Optics
The
Coolpix 5700 features an 8x Nikkor 8.9-71.2mm ED lens, the equivalent of a 35-280mm
lens on a 35mm camera. The maximum aperture varies from f/2.8 to f/4.2, depending
on the lens zoom setting, with the largest aperture available when the lens
is at its maximum wide angle focal length. Apertures are adjustable in 10 steps
with one-third EV increments, and are created by a seven-blade iris diaphragm.
(The seven-blade diaphragm is a nice but subtle touch - it will produce less
distortion in sharp, specular highlights than apertures made by diaphragms with
fewer blades in them, and hence more irregular shapes. The seven-blade iris
also provides finer-grained aperture control than simpler designs.)
Focus on the Coolpix 5700 operates under automatic or manual control, and features Macro and Infinity focus modes as well. The Coolpix 5700's autofocus mechanism employs a contrast-detection method, which determines focus from a five-area multi-pattern or spot AF area. There are five possible focus zones (center, top, bottom, left, right), useful for achieving accurate focus on off-center subjects, although all are clustered rather closely about the center of the frame. (I'd really like to see them extend a bit further out toward the edges, perhaps a third of the distance from their current locations toward the edges of the frame.) The Focus option under the settings menu defaults to AF area selection under automatic control, or lets you explicitly set the location of the focus area. (This last is a nice feature that works well when combined with the spot metering mode, which can likewise be directed to determine exposure from the same five zones.) In the "Auto" option for focus area selection, the camera chooses the area corresponding to the object closest to the camera. When the area focus option is set to Off, the camera bases focus on the central area. (One Playback mode information screen displays a focus area overlay, and shows which focus area was chosen for each image, by highlighting the appropriate set of marks in green.)
Two AF modes are also available: Continuous AF and Single AF. Continuous AF mode means that the camera constantly adjusts the focus, good for moving subjects. In Single AF mode, focus is only determined when the Shutter button is halfway pressed. When the LCD viewfinder is off, the camera remains in Single AF mode.The camera continuously focuses by default, but you can select the Single AF mode through a menu option.
The manual focus option is accessed by pressing the Focus Mode button and turning the Command dial. A distance scale in the LCD monitor reports current focusing distance in a very general sense, showing a bar that extends from a macro symbol on one side to an infinity symbol on the other. The minimum focusing range depends strongly on the lens zoom setting, so the focus-distance display turns red if you try to manually focus closer than the lens can support at its current focal length. I have to say that I dislike the 5700's distance readout because it makes it difficult or impossible to know the actual focusing distance you've selected. I've often had occasion to set an approximate manual focus distance in advance of a shot, based on my estimate of the subject's distance. (After-dark candid and wildlife photography are two situations where I've frequently needed to do this.) I would think Nikon could use the combination of lens focal length and stepper motor position to derive the actual focusing distance. - Certainly, I've seen numeric distance readouts on cameras from a variety of other manufacturers, so it's technically possible.
For those situations when you can actually point at your subject long enough to set the focus visually, a "Focus Confirmation" option (available as a menu selection in Record mode) applies a strong "sharpening" operator to the LCD display. The result is that the LCD image very clearly "snaps" into focus when proper focus is achieved, making the LCD display much more useful that it ordinarily would be for manual focusing. Focus Confirmation can be set to be on all the time, off all the time, or only on when the camera is being manually focused. - This is another Nikon trick that I'd like to see more camera manufacturers adopt.
The Coolpix 5700's digital telephoto feature is enabled through the Zoom option under the Setup menu, and enlarges images as much as 4x. An indicator on the LCD monitor displays the current level of digital zoom at each step (from 1.1x to 4.0x). Keep in mind though that digital telephoto only enlarges the center of the image, reducing resolution in direct proportion to the amount of digital zoom used. The 5700 appears to automatically switch to center-weighted metering and a center autofocus target when digital zoom is active. Also under the Zoom menu option, you can set the zoom speed and activate the Fixed Aperture function, which keeps the aperture fixed as the lens zooms. (This last being a very handy option when working with studio strobes or other strobes with fixed output levels and no exposure feedback from the camera.) In my own use of the camera, I couldn't see much difference in zoom speed between the "fast" and "slow" options, a difference of 0.25 seconds in the time it took to run the zoom across its full range. (2.15 seconds at the "fast" zoom setting, 2.4 seconds at the "slow" one.) It seemed that the "slow" setting made it a bit easier to adjust the zoom setting in small increments, but the difference between fast and slow was again pretty subtle.
There's a set of body threads around the base of the lens barrel, presumably for attaching an adaptor barrel for accessory lenses. I don't know how useful these threads will be though, given the significant distance the front element of the 5700's lens travels when it zooms, extending much further in the telephoto than the wide angle position. I guess you could have a lens adapter for use with a teleconverter that would position the adapter lens beyond the furthest travel of the 5700's lens. You couldn't use that same adapter for a wide angle accessory lens though, as it produce severe vignetting. - And if you attached a wide angle lens close enough to work properly when the camera lens was set to its wide angle position, it would be easy to damage the lens mechanism if the camera tried to rack the lens out to the telephoto setting when it was turned on.
Autofocus performance under low light on the 5700 seems similar to that on prior Coolpix models, but suffers relative to some of the competition due to the lack of an AF-assist illuminator. In my informal testing, the AF system could focus on sharply-defined, high-contrast objects at light levels as low as 1/4 foot-candle. (About 2.6 lux.) In actual use with typical subjects though, you shouldn't expect reliable AF performance at levels less than twice that, since contrast-detect AF is very dependent on the contrast of the subject, and responds much better if the subject has sharply-defined edges in it. With less contrasty or less sharply-defined cameras, you'll need more light for accurate focusing.
There's good news for macro fans with the 5700 too: Like the rest of the Coolpix line, it's an excellent macro performer: Minimum macro coverage area is a tiny 1.16 x 0.87 inches (29.6 x 22.2 mm), by my actual measurements.
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