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Nikon Coolpix 8400 By: Shawn Barnett & Dave Etchells (none) Select a topic Reference: Datasheet 8400 Sample Images 8400 Imatest Results --------------------------------- 1. Intro and Highlights 2. User Report 3. Design 4. Viewfinder 5. Optics 6. Exposure & Flash 7. Shutter Lag & Cycle Time Tests 8. Operation & User Interface 9. Camera Modes & Menus 10. Image Storage & Interface 11. Video, Power, Software 12. Test Results & Conclusion --------------------------------- Print-Friendly Review Version Additional Resources and Other Links Reader Comments on 8400 Review --------------------------------- Digital Camera Comparometer (TM) --------------------------------- <-- Digital Cameras (Home) <-- Digital Camera Reviews Index <<Viewfinder :(Previous) | (Next): Exposure & Flash>> Page 5:Optics Review First Posted: 09/16/2004, Updated: 12/13/2004

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The Coolpix 8400 features a 3.5x Nikkor 6.1-21.6mm ED lens, the equivalent of a 24-85mm lens on a 35mm camera. The maximum aperture varies from f/2.6 to f/4.9, depending on the lens zoom setting, with the largest aperture available when the lens is at its maximum wide angle focal length. Minimum aperture is f/7.2 at wide angle, 7.7 at telephoto, and a maximum of 7.9 somewhere in between. (The minimum aperture fluctuates both up and down slightly as you zoom from wide to telephoto focal lengths.) 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 8400 operates under automatic or manual control, and features Macro and Infinity focus modes as well. The Coolpix 8400's autofocus mechanism employs a combination of infrared and contrast-detection methods. The front-mounted infrared focus sensor establishes rough focus, after which the CCD-based multi-point AF system sets final focus. One interesting consequence of the dual nature of the 8400's AF system though, is that the camera focuses much more quickly when the Auto Area Focus Mode is turned off, allowing the hybrid AF system to be used. (A few important notes here: The camera's factory-default setup is to have the AF Area Mode disabled and Hybrid AF enabled, which is the fastest focusing mode. It's possible that a camera may have been set up differently in the store by a salesperson though, so you should check explicitly to see that the camera is set up properly for fastest shutter response. If you disable AF Area Mode, but leave the camera in Normal vs Hybrid AF mode, you'll see little or no speed improvement. You need to disable AF Area Mode and set the focusing to Hybrid to get the best shutter response. Note too, that Manual AF Area selection is only slightly faster than Auto Area selection, as both modes disable the Hybrid AF system.)

The Focus option under the Record mode settings menu allows AF area selection under automatic control, or lets you manually set the location of the autofocus area. (This last is a nice feature that works well when combined with the spot metering mode, which can likewise be directed to link exposure to the same zone.) In the "Auto" option for focus area selection, the camera chooses the area corresponding to the subject closest to the camera. When the area focus option is set to Off, the camera bases focus on the central area. 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. It should be noted that because the camera is always focusing, it will make a noise as long as the camera is on, because it is constantly trying to focus and refocus on the selected AF point. Many users have written us in the past about cameras operating in this mode, finding the constant burbling of the focus actuator disturbing. Continuous AF mode also tends to use power more quickly, so it should only be used when necessary. In Single AF mode, focus is only determined when the Shutter button is halfway pressed.

The fully manual focus option is accessed by pressing the AF button on the camera's side 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 8400'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 focus-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 than 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 8400'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 a bar graph showing the approximate level of digital zoom. 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. Also under the Zoom menu option, you can turn the digital zoom off 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.)

There's a set of body threads around the base of the lens barrel, protected by a metal ring, for attaching an adapter barrel for accessory lenses. The 8400 can accept wide, telephoto, and fisheye lenses with the use of an optional adapter.

Autofocus performance under low light on the 8400 seems similar to that on prior Coolpix models, aided by an AF-assist light nestled next to the hand grip for better results. In my informal testing, the AF system could focus on sharply-defined, high-contrast objects in total darkness out to about 6 feet or so, but it did considerably better with at least some ambient light, and the focus performance was also very dependent on the contrast level of the subject involved. Though there are many similarities between the Coolpix 8400 and it's brother the 8800, they do differ a fair bit in their ability to focus well in low light. This is due not only to the shorter zoom, but also to the phase-detect IR AF assist or prefocus system mentioned earlier. The bottom line is that the Coolpix 8400 focuses much more quickly in dim lighting than does the 8800.