Nikon's entry-level DX DSLR with a vari-angle screen and 16.2MP sensor.
The Nikon D5100 was released in April 2011 as the first D5x00-series DSLR with a fully articulating rear LCD, enabling low-angle, overhead, and self-facing composition that fixed-screen predecessors could not achieve. The 16.2MP sensor without optical low-pass filter improved resolving capability over the D5000's 12.3MP design. The D5100 was aimed at enthusiast photographers who wanted a compact, capable DSLR with articulating screen functionality at an entry price point.
The 16.2MP DX-format CMOS sensor without optical low-pass filter pairs with the EXPEED 2 processor. The 11-point AF system — with one cross-type centre point — provides reliable acquisition for standard photography. Burst shooting runs at 4fps. 1080p video records at up to 30fps. The fully articulating 3-inch 920k-dot LCD enables low-angle, overhead, and reverse framing. No weather sealing. Battery life approximately 660 shots using the EN-EL14, body weight approximately 565g with battery and card, single SD/SDHC/SDXC slot.
The D5100's articulating screen was its primary practical feature for the price tier — enabling tripod-mounted landscape and video work where the lens points downward or overhead without the body contortion required by fixed-screen cameras. The OLPF-free 16.2MP sensor provides better fine-detail resolution than the low-pass-equipped D3100. The 11-point AF with one cross-type point is adequate for static and casual moving subjects; fast action tracking is a limitation.
On the used market the D5100 is very affordable. Condition checks: articulating screen hinge (a frequently used mechanical joint), shutter count via EXIF, and EN-EL14 battery health. The D5200 (2012) provides a 24.1MP sensor and 39-point AF at a modest premium. The EN-EL14 battery is shared across D3200, D3300, D3400, D5200, and D5300 — spares are widely available. There is no in-body AF drive motor — AF-S and AF-P lenses autofocus; older AF-D lenses mount and meter but require manual focus. Compatible with all Nikon F-mount lenses.