Nature Photography

Almost all backpackers seek to minimize the weight and bulk of gear carried and this is where the Nikon D90 betrays for the first time a slight weakness. At 708g (including battery and a SD card), there are surly more light-weight alternatives for multi-day treks but quality has simply an impact here. However, other than that the Nikon D90 provides pretty much everything you need for outdoor photography. Nikon's lens portfolio offers a huge number of "landscape"/"nature"-related lenses through the all price ranges and leaves nothing to be desired, if you select your lenses carefully.
The DOF-button of the camera is placed in an ideal position on the right bottom close to the lens mount and it is a useful feature in combination with the excellent viewfinder. In addition, the battery manages about 800, which is pretty useful in regions without reliable power supply. Nikon's dust reduction system seems to operate faultlessly and is therefore ready for dusty environments. A body sealing would perfect this DSLR and make the Nikon D90 suitable for fairly difficult outdoor missions.

Macro Photography

The Nikon D90 features a live-view mode very useful for macro photography, as the object can be enlarged up to 6.7 times for accurate manual focusing. The Nikon live-view mode works fine and the handling is intuitive. The Nikon D90 is capable of producing great macro results in combination with one of the good Nikon macro lenses and a ring-flash unit.

The Sigma AF 150mm f/2.8 APO EX macro DG D is one of the few third-party lenses that can play in the league up there with the big boyz. The performance figures are excellent and leave really nothing to be desired across all tested quality characteristics. (lens review)

Night Photography

Just like most of its competitors, the Nikon D90 features bulb exposure, but unfortunately the exposure button has to remain pressed during the whole exposure. In addition the camera offers only a maximal exposure time of 30 seconds. The Nikon D90 has a TTL controlled flash socket for the use of external flashes, but the build-in flash with a guide number of approx 18 is a quite good alternative when an external flash is not available.
The ISO sensitivity sets the benchmark. ISO values can be set between ISO200 and ISO3200 in steps equivalent to 1/3EV and the Nikon D90 produces usable results even with high sensitivity.
In extreme low-light situations, the Nikon D90 can take advantage of an AF assist illuminator to assist the focus operation, but this is rarely the case as the AF speed convinces also with bad lighting conditions.
Nikon doesn’t follow the trend of camera built-in image-stabilizers. Similar to Canon and Panasonic they provide lenses with their own built-in image-stabilizer, the Nikon’s Vibration Reduction (VR). This works fine but not really better than a built-in image-stabilizer.

Portrait Photography

The Nikon D90 provides all the features required for portrait photography. In combination with one of Nikon's excellent fixed focal length lenses and flash units, it is suitable for high-quality portraits. For newbies or casual photography, it even offers a face recognition system that can be switched on in Live View mode - a nice gimmick, but not really needed for more serious portrait photography. The flash synchronization is fast enough for the typical focal lengths used for this purpose.

If you´re looking for a portrait lens or a similar application where you would like to isolate an object from its environment, we would recommend the Nikkor AF 85mm f/1.8 D. (lens review). The principal capability is slightly limited by the APS-C format sensor which "costs" about 1 f-stop in depth-of-field potential compared to a full format DSLR.

Sports Photography

With continuously up to 4.5 pictures per second, the Nikon D90 is actually geared for fast sport action shots. In RAW mode however, the frame rate slows down after 11 frames in succession due to the memory buffer. On top of that, Nikon has limited the maximum number of continuous frames to 100. The AF speed and the accuracy of the Nikon D90 are impressive, even in dark conditions. The excellent AF speed guarantees a sharp sports picture even in continuous AF mode.
The maximum shutter speed is 1/4000s – nothing special here but usually sufficient for most kind of action photography. However, the X-Sync speed of 1/200s is one of the slower implementations in this class.

A wide range of lenses which are suitable for action photography is available for the Nikkor mount. For example, the Sigma AF 100-300mm f/4 EX HSM DG, one of the most impressive Sigma lenses tested to date. It is able to deliver a near-flawless performance with great resolution figures, low vignetting, low distortions, low CAs and a very decent bokeh. (lens review)