Fitting into Nikon’s lineup between the D5000 and D3000, the new D3100 tops them both in a number of areas, including pixel count (14.2 MP vs. 12.3 for the D5000 and 10.2 for the D3000) and full 1080p HD video with full-time autofocusing during recording. Like the D3000 and D5000, the D3100 doesn’t have a built-in AF motor, so the camera will provide auto focusing only with lenses that have the motor built in—primarily, the AF-S Nikkors, including the new low-priced AF-S 55-300mm zoom that was introduced with the camera.
For outdoor shooters who want to record the location in the metadata for each image, the D3100 offers a socket that accepts the cord from the optional Nikon GP1 GPS unit or the cord for the MC-DC2 remote control.
Automatic Chromatic-Aberration Correction
Higher-end Nikon bodies have provided automatic correction of chromatic aberration for a while, but now this very useful feature comes to an entry-level model. No more purple/green fringing; the camera automatically corrects it as you shoot.
New 14.2-Megapixel CMOS Sensor
Interestingly, at the time of its announcement, the D3100 offered the highest pixel count of any Nikon DSLR except the $7,999 24-megapixel, full-frame D3X. The new 14.2-megapixel CMOS DX (APS-C) sensor and new EXPEED 2 processing make possible full HD video and provide a normal ISO range of 100-3200, expandable to 6400 and 12,800.
Improving on the D3000’s Guide Mode, the D3100 will lead a beginner through just about any shooting need, while providing full control of everything for the more experienced user.
Especially useful for outdoor shooters who often change lenses in the field, the D3100’s Automatic Image Sensor Cleaning system uses ultrasonic vibrations and an exclusive Airflow Control to remove dust from the sensor assembly.
Light And Compact
At 4.9x3.8x2.9 inches and 16 ounces, the D3100 is easy to carry far afield. It’s sold with the AF-S DX Nikkor 18-55mm ƒ/3.5-5.6G VR zoom; add the low-cost new AF-S DX Nikkor 55-300mm ƒ/4.5-5.6G VR zoom and you have a lightweight outdoor shooting system with 35mm-camera-equivalent focal lengths from 27mm to 450mm.