ABSTRACT
Refraction is a physical property of light that allows lenses to form an image. When light passes from one medium to another with a different optical density, it bends, or refracts, because its speed changes. The iris diaphragm is an adjustable mechanism that regulates the amount of light that passes through a lens. The sweet spot of a lens refers to the f-stop setting at which it produces the highest possible image quality in terms of contrast, color rendition, sharpness, vignetting, and chromatic aberrations, among others. Lenses can register images at any f-stop if enough light is available, but they will generally produce an optically superior image when set roughly halfway along the f-stop scale. Angle of view is a measurement of how much of a scene or a subject a lens can encompass across the x, y, or diagonal axes, expressed in degrees.
