A Ball Lens consists of a highly transparent spherical ball, usually made of solid glass (fused silica) or another optical material with index of refraction less than 2. Most ball lenses are made with ...

Photography blogger Lau offers a plain-English explanation of two of the most confusing concepts in photography: aperture and focal length. A highlight: Lenses with larger apertures are faster because ...

Why is 'depth of field' or 'depth of focus' greater with a smaller aperture on a camera or when the iris in your eye is closed down to a smaller pupil size? Ever since people first noticed that you ...