A mirrorless camera is a photo camera featuring a single, removable lens and a digital display.The camera does not have a reflex mirror or optical viewfinder like a digital single-lens reflex (DSLR) camera, but may have an electronic viewfinder.Many mirrorless cameras retain a mechanical shutter. Like a DSLR, a mirrorless camera accepts any of a series of interchangeable lenses …

The American system of manufacturing was a set of manufacturing methods that evolved in the 19th century. The two notable features were the extensive use of interchangeable parts and mechanization for production, which resulted in more efficient use of labor compared to hand methods. The system was also known as armory practice because it was first fully developed …