The autofocus system has been expanded to 51 focus points with 15 cross-type autofocus points in the middle. This sensor is called the Multicam 3500DX, and it supports lenses with an aperture of up to f/8. The autofocus sensor is assisted by a Scene Recognition System RGB sensor with 2016 pixels for measuring the light. The contrast autofocus detection during live-view and filming has been improved for better accuracy and speed. The D7100 can take 6 frames per second in JPG and 12-bit RAW, 5 fps in 14-bit RAW and 7 fps with the 1.3x crop mode. This is made possible by the Expeed-3 image processor. The fastest shutter speed is 1/8000.
The 1.3x crop mode is an extra cut-out of the 1.5x crop DX sensor in the Nikon D7100. It increases the zoom range of lenses. It also increases autofocus coverage, since the autofocus points reach to the edge of the image. In this mode you're left with a resolution of 15.4 megapixels, and the mode is also available in film mode.
In the crop mode a frame with a black edge is visible in the viewfinder which has 100 percent coverage and a zoom of 0.94x. The viewfinder also has a virtual horizon feature, which was only available in live-view on the D7000. It helps you take horizontal photos. The data displayed in the viewfinder uses OLEDs, which makes it more visible. The D7100 features an autofocus motor for old AF lenses and an aperture sensor for manual focus lenses.