The Nikon APS-C refers to a specific sensor size used in Nikon's digital cameras, particularly in their DSLR and mirrorless models. APS-C sensors are smaller than full-frame sensors, measuring approximately 22.5 x 15.0 mm. This size allows for a crop factor of about 1.5x, meaning that a lens will appear to have a longer focal length compared to its full-frame equivalent. Nikon's APS-C cameras are popular among both amateur and professional photographers due to their balance of image quality, size, and cost. They offer a wide range of compatible lenses and accessories, making them versatile for various photography styles, from landscapes to portraits.