Nikon DX refers to a specific format of digital cameras and lenses produced by Nikon. It is designed for cameras with an APS-C sized sensor, which is smaller than the full-frame sensors found in some other models. This format allows for a crop factor of approximately 1.5x, meaning that a lens will appear to have a longer focal length compared to its full-frame equivalent. The Nikon DX system includes a range of cameras, such as the Nikon D3500 and Nikon D7500, as well as a variety of compatible lenses. These cameras are popular among amateur photographers due to their affordability, lightweight design, and user-friendly features, making them ideal for everyday photography and learning.