Lenses Are classified by their Focal Length
The distance from the optical center of a lens to the front surface of the imaging device.
Short Focal Length Wide Angle View
Short Focal Length EXAMPLE Entire Football Team
Long Focal Length Narrow Angle View
Long Focal Length EXAMPLE One Football Player
Zoom Lens Variable Focal Length
Zoom Range How close to how far a lens can see
Lens Speed How much light can pass through a lens
Fast Lens Lets a great amount of light to pass through
Fast Lens Use in the evening, when there isn’t much light. For low light settings
Slow Lens Lets a small amount of light to pass through
Slow Lens Use this on bright, sunny days For bright light settings
Iris Adjustable lens opening mechanism
Aperture Hole in center of iris Measured by f-stops
Aperture Similar to the pupil of your eye
Aperture Can adjust larger or smaller depending on the amount of light
Aperture What type of aperture opening would you use for a sunny day?
Aperture What type of aperture opening would you use for a dark room with only a candle for light?
Auto Iris Many cameras have auto iris Adjusts automatically depending on setting
Focus When subject in viewfinder is sharp and clear.