It introduced Nikon's new EXPEED 2 image processor and was the first Nikon DSLR featuring full high-definition video recording with full-time autofocus and H.264 compression, instead of Motion JPEG compression.

It was also the first Nikon DSLR to provide high-definition video recording at more than one frame rate.

[6] With any other lens, the camera's electronic rangefinder can be used to manually adjust focus.

[7][8] Can mount unmodified A-lenses (also called Non-AI, Pre-AI or F-type) with support of the electronic rangefinder and without metering.

[9] The Nikon D3100 has available accessories such as:[10] The D3100 has received many independent reviews[31][32] and image comparisons at all ISO speeds.