Lenses are used in cameras, telescopes, binoculars, microscopes and corrective glasses. A lens can be converging (convex) or diverging (concave). The centre of the lens is called the optical centre C.

Telescopes are great tools for observing the heavens, or even surrounding landscapes if you have the right vantage point. You ...

Canon is rumored to be working on an ultra-wide, ultra-fast prime lens for its mirrorless cameras, potentially a 14mm f/1.4.