For the seasoned photographer, it is the internals of the D5100 that make it most impressive. The sensor and processor are the same as those used in the D7000.
The sensor is a 16.2-million-pixel CMOS unit in an APS-C format (or DX as Nikon terms it). It outputs a 4928×3264-pixel image in a 14-bit raw file or compressed JPEG, and combinations of the two. This equates to a 10.9×16.4in print at 300ppi (practically A3).
The image processor is Nikon’s Expeed 2 unit and various teardowns of the camera posted on the internet have revealed 3GB of SDRAM alongside it to ensure fast processing, although this is less than the 4GB believed to be in the D7000.
The combination of sensor and processor has shown impressive noise performance in the D7000, and in the D5100 it offers the same ISO 100-6400 standard range with extended settings up to ISO 25,600 (Hi2).
Video is captured in 1920×1080-pixel HD at 30fps, 25fps or 24fps, saved in a MOV format with H.264 compression, as on the D7000. Operation in video is completely automatic, regardless of the shooting mode set on the dial.
The lens mount is the standard Nikon F fit and is fully compatible with AF-S and AF-I optics. As the camera doesn’t contain a built-in AF motor, other G- and D-type lenses will not provide autofocus but will work with manual focusing. Stabilisation remains an optical process and is performed in the VR lenses rather than in the body, including on the standard kit lens, the Nikkor 18-55mm f/3.5-5.6 VR. The body does contain a sensor-cleaning system, though, which vibrates the low-pass filter and uses an airflow system to remove particles of dust.
The 3D Color Matrix Metering II system operates via a 420-pixel RGB sensor. As well as full matrix metering, it offers centreweighted and spot options, with the latter covering 2.5% of the frame. Exposure compensation is available in 1/2 and 1/3 stops to a wide ±5EV. Bracketing can be performed for exposure and white balance in three frames, and two frames for Active D-Lighting. The focusing is care of Nikon’s Multi-CAM 1000 system, sporting 11 focus points, including a central cross-type point, and features the impressive 3D-tracking system seen on previous models like the D7000 and D3100. There is a choice of auto, single and continuous servo modes for the focusing, while in live view mode there is a full-time servo that works to continually focus even when shooting video, as well as face priority and subject tracking area modes. The contrast-detection focusing in live view now has improved algorithms to improve the focusing speed.
Image: The night vision effects mode uses an auto ISO of up to Hi4 (equivalent to 102,400) and automatically turns the image to monochrome to reduce signs of noise
The choice of exposure modes is vast on the D5100, offering the standard selection on program, manual, shutter and aperture priorities, alongside a full auto, a set of five direct scene modes, plus another 11 via a scene submenu.
On top of this there is also the set of seven new special effects modes, as detailed in the Features in use panel.
The retouch menu provides an extensive list of post-capture adjustments that can be made in-camera to both raw and JPEG files, including D-Lighting, distortion control and filter effects.
There is also raw processing, which allows various adjustments to be made to raw files before converting the file to a JPEG, and edit movie, which allows you to trim your video clips on the move.
The built-in flash is spring-loaded and, when the flash button is pressed or it is required in an auto mode, it springs up and sits nice and high above the camera body. It has a guide number of 13m @ ISO 100, although this is falls to 12m when used in auto settings (auto, portrait, child, close-up and night portrait). It uses iTTL controls for standard and fill-flash abilities, which also extend to flashguns controlled via the hotshoe. Wireless flash is supported, but the camera doesn’t include a wireless controller so an SB-700, SB-800 or SB-900 flashgun must be mounted, or an SU-800 controller used.
The camera uses SD cards for storage and is fully compatible with SDHC and the new SDXC cards. In burst mode, the D5100 will shoot at up to 4fps. Using a SanDisk 8GB Extreme Pro SDHC card, it will maintain burst shooting for up to 16 raw files, ten combined raw+JPEG files, or an impressive 100 JPEGs. Individual write times for files take around 1sec for a JPEG, 1.5secs for raw and 2secs for a combined raw and Fine JPEG.
Features in use: Special effects
The special effects are a series of seven creative looks that are selected via an effects submenu on the shooting mode dial. They work much like scene modes, in that the camera takes control over the main camera controls for you, but each offers a degree of processing or effect to give them a distinct look.
The effects include colour sketch, miniature, selective colour, silhouette, high key, low key and night vision. There is some control within the settings: colour sketch, which produces an almost posterised effect, allows control over vividness and outlines; miniature mode, which produces a tilt-shift effect, allows you to vary the width of the in-focus area and swap between horizontal and vertical planes; selective colour allows the user to pick a total of three colours and vary their vibrancy individually.
Night vision is perhaps the most interesting, though, as it uses a specially extended Hi4 ISO setting to allow shooting at up to ISO 102,400. The ISO and exposure are automatic, so control is limited, and images are saved in b&w to minimise the effect of noise at higher settings, although it is still an impressive feature for extreme low-light shooting.