Nikon D3100Look and feel. The Nikon D3100's body is all-new, but its dimensions and weight are similar to that of the D3000: 4.9 x 3.8 x 2.9 inches (124.5 x 96.5 x 73.7mm) and about 1.1 pounds (511g) without lens, or 1.7 pounds (777g) with the 18-55mm VR kit lens. Since most controls have similar placement, the new body will offer a shallow learning curve for D3000 and Nikon D40 owners. Several new controls have been added, both for new features, and quicker access to existing ones.
The Nikon D3100's grip is deeper, compared to that of the D3000, and the thumb grip on the rear of the camera has simultaneously been updated with a small rubber panel. These changes make the D3100's body more comfortable to hold -- especially for photographers with larger hands -- and provide a steadier, more reassuring grip.
Like most recent Nikon digital SLRs, the D3100's cut is considerate of the left hand, with a slight rounding of the edge, seen in the lower right of the picture above. This makes it just a little more comfortable to rest the Nikon D3100 in your left palm as your fingers reach out to adjust the zoom and focus rings.
Looking at its front panel, a new three-hole microphone grille can be seen just above the D3100 logo, for use with the camera's new Full HD movie mode. Absent, though, is the infrared remote receiver in the handgrip. Unlike the D3000, the D3100 only makes provision for cabled remotes, and cannot function with an infrared remote.
The Nikon D3100's Mode dial features the same thirteen operating modes as the D3000. Beneath it, jutting out from the right, lies a new Drive Mode switch, which allows the D3100 to be quickly switched between Single, Continuous, Self-Timer, and Quiet modes without needing to resort to the camera's menu system.
Like the D3000 before it, the Nikon D3100 is shipping with Nikon's 18-55mm VR image-stabilized lens. It's an upgrade from the non-image-stabilized kit lens bundled with earlier models, but there's an element of compromise in this change, because the VR kit lens lacks the Extra-low Dispersion glass found on the non-VR equivalent, which is a shame.
Lens mount. Like the D3000 before it, the Nikon D3100 sports an AF-S lens mount, which lacks autofocus support for the older AF lenses whose focus mechanisms were driven from the camera. These lenses have what looks like a little screwdriver slot on their mounting flange that couples with a protruding, screwdriver-looking shaft on the camera body. A motor in the camera body is thus required to drive the lens mechanics to adjust focus.
More recent Nikkor lenses have motors built into the lens body, which tend to be both faster and quieter than the old-style drive system, as well as allowing the camera body to be lighter, smaller and cheaper. These newer lenses carry an AF-S or AF-I designation in their name, and are the only types of lenses the D3100 can autofocus with. CPU-equipped lenses lacking built-in focus motors can be used in manual focus mode, and type G or D lens types will also support full 3D color matrix metering for more accurate exposures, particularly when flash is being used. (You can tell CPU-equipped lenses by the set of five electrical contacts arrayed on the side of the lens flange.)
Focus and Exposure. The Nikon D3100 shares the same Multi-CAM 1000 phase-detection autofocus sensor module that's previously appeared in the D3000 and D5000, among others. The Multi-CAM 1000 module offers 11 focusing points, of which the center point is a cross-type sensor. While the AF sensor itself is unchanged, Nikon has updated the viewfinder point display. In the D3000, the approximate AF point locations were indicated with dense black marks in the viewfinder. For the Nikon D3100, these have been replaced with much fainter markings, illuminated by single LEDs. One further change to the viewfinder display, perhaps related to this change, is that the Nikon D3100 lacks the on-demand grid display function from the D3000.
The Nikon D3100 also retains the D3000's Scene Recognition System, 3D Tracking capability, and selection of auto-area, single-point, and dynamic-area AF modes. The Multi-CAM 1000 system integrates the AF sensor data with information from the 420-pixel RGB 3D Color Matrix II metering sensor, allowing the system to better track objects moving through the scene. The Multi-CAM 1000 sensor has a detection range of -1 to +19 EV at ISO 100 / 68°F. The selection of exposure modes is unchanged from the Nikon D3000, with the D3100 offering Full Auto, Program AE, Manual, Aperture Priority, and Shutter Priority modes, as well as a selection of six scene modes -- Portrait, Landscape, Child, Sports, Macro, and Night Portrait. Operation of the Auto exposure mode has been changed, however, as the D3100 will now automatically pick a scene type from among the six scene modes when first entering Auto mode. Metering modes include matrix, center-weighted (weight of 75% given to 8mm circle in center of frame), and spot (2.5% of frame centered on selected focus point).
Guide mode. The Nikon D3100 further builds on the user friendly Guide mode from the D3000, which is accessed from the Guide Mode position on the Mode dial. When placed in this mode, the Nikon D3100 will greet users with a friendly graphical interpretation of the menu system, with icons labeled Shoot, View/Delete, and Set up. When in the Shoot menu, the photographer is asked a number of questions, and the Nikon D3100 then offers guidance on what to set -- and importantly, why each suggestion is being made. A helpful change from the D3000's Guide mode is the addition of reference photos that demonstrate the effect of settings being applied. For example, as shown in the screenshot (left), when the Guide mode recommends shutter adjustment, it also offers an image of a child kicking a football as an example of the adjustment's effect. As the shutter speed is changed, the reference photo is updated, showing the motion blur at slower shutter speeds, and a sharper image at faster shutter speeds. For aperture adjustment, similar images are available, with the level of background blur changing as the aperture value is adjusted.
Another change to the Guide mode is that, when the user has stepped through the process of answering questions and adjusting their setup per the camera's recommendations, the Nikon D3100 will now ask whether the user wants to shoot a still image using the optical viewfinder or Live View functions, or capture a video. Depending on the answer, the camera will be automatically placed in the correct mode.
Price Ranges: N90,000-N120,000