Nikon D5000 Digital Camera Review$729.95
Even with noise reduction off entirely, image noise never rises beyond 2%, and the Normal level keeps noise at about 1% even out to ISO 3200. More on how we test noise.
As with most Nikon cameras, the D5000 has a range of official ISOs, indicated numerically in the menus, plus additional extended ISO settings above and below. In this case, the official ISOs run from 200 to 3200. The lower extended range settings are Lo 0.3, equivalent to ISO 160, Lo 0.7 (ISO 125) and Lo 1 (ISO 100). On the high side there are Hi 0.3 (ISO 4000), Hi 0.7 (ISO 5000) and Hi 1 (ISO 6400). Why not just treat all the ISO settings equally? Because, as Nikon points out, the Hi settings are subject to increased image noise and color distortion, while the Lo settings have lower contrast.
In addition to the standard controls there is an Auto ISO setting, used in Auto shooting mode and by default in scene modes. When shooting in program, shutter-priority, aperture-priority or manual modes, turning the Auto ISO setting on will only affect exposure if the camera determines that an appropriate exposure can't be achieved at the ISO setting chosen by the shooter. A maximum allowable value when shooting in Auto ISO mode can be set.
When shooting with the viewfinder, we found the autofocus system quite speedy and accurate in bright light. The camera struggled a bit with dimmer indoor illumination, but always managed to lock on after a slight delay.
The Nikon D5000 uses an 11-point autofocus system with one cross-type sensor. The camera offers four focus modes: Single-servo, continuous-servo, auto-servo (which jumps between single and continuous depending on the subject), and manual.
The D5000 has a particularly bright autofocus assist lamp located on the front of the camera, below the mode dial, which we found very helpful when shooting in dark rooms. Nikon gives its effective range as 1 ft. 8 inches to 9 feet 10 inches (0.5 to 3.0m).
In our long exposure test, which measures both color accuracy and image noise levels at several shutter speeds, the Nikon D5000 turned in very strong results, just a hair's breadth lower than the Canon Rebel XS overall and significantly better than the competitively priced, video-enabled Canon T1i.
To test long exposure performance, we shoot the X-Rite ColorChecker Chart at low light levels (20 lux or below), at shutter speeds ranging from 1 second to 30 seconds. We shoot with long exposure noise reduction turned on and turned off. This feature works by taking a second exposure with the shutter closed, then mathematically eliminating the noise found in the second dark exposure from the original captured image. Since image noise is inherently random, we've found this noise reduction feature rarely does much good and, in many cases, actually produces a lower-quality final image. For the D5000, though, long exposure noise reduction did produce improvements with shutter speeds of 10 seconds or slower, and didn't impact color reproduction. More on how we test long exposure.
Color accuracy varied little as shutter speeds got longer, a good result. Image noise hovered around 0.8% across the range of shutter speeds, with very little variation. Again, this is a very strong performance.
The following chart shows the scoring results for our group of tested cameras, with the Nikon D90 nearly identical to the Rebel XS at the head of the pack.
Video: Low Light Sensitivity
Like all DSLRs the Nikon D5000 has a huge CMOS image sensor that is far larger than what you get on a consumer HD camcorder. This large sensor should, in turn, give the camera a significant boost in low light situations. Surprisingly, however, the D5000 didn't do as well with low light sensitivity as we expected. The camera wasn't bad, it needed only 11 lux of light to reach 50 IRE on our waveform monitor, but this isn't the kind of performance that is really noteworthy. Numerous consumer camcorders had better low light sensitivities than the Nikon D5000, especially when using alternate frame rates like a 24p or 30p mode.