Lenses Basic Terminology
Check us out at http://www.tutorvista.com//videos For a simple lens the focal length is defined as the distance between the camera sensor and the lens when focused at infinity. For a given object to lens distance, the greater the focal length and the greater is the visible detail in the image and the smaller the field of view (FOV). The three main classes of focal lengths are : wide angle, normal and telephoto. For each sensor format these definitions correspond to different focal lengths ranges. Zoom lenses allow for a continuous change of focal length within a range. See the lens calculator to determine the correct focal length for your sensor, object distance and field of view. All these 3 parameters are needed to calculate the lens focal length.