CIRCLES OF CONFUSION

When we talk about a lens, we often describe it by the film format or sensor size that it’s designed to work with. Super 35mm lenses are designed to work with Super 35mm film or sensors that are around the same size; Super 16mm lenses are designed to work with Super 16mm film or similar sensors, etc. This can be confusing in itself, as we talk about lens focal length in millimeters, as well. You can have a 35mm (focal length) Super 16mm lens, for instance, and a 16mm (focal length) Super 35mm lens.

via Sensors & Circles | HDVideoPro.com.