Camera lenses are made using several different processes, depending on the element and the design. In general, lens elements may be ground and polished from glass, and some are also molded—especially specialized molded elements such as certain precision glass moldings. Manufacturers use different techniques for different optical needs, materials, and production methods.

The arrangement of elements and groups inside a lens is determined during the optical design process. Designers choose the number, shape, type, and spacing of elements to achieve goals like sharpness, distortion control, focus behavior, size, and cost. Those elements are then assembled into groups that work together to produce the final image.

If you want to see real examples, major makers such as Canon and Nikon have published overviews of their lens design and manufacturing processes, and educational videos like "How It’s Made" also show the basics of lens production.