explain focal length
Answers
Answer:
Explanation:Focal length, usually represented in millimeters (mm), is the basic description of a photographic lens. It is not a measurement of the actual length of a lens, but a calculation of an optical distance from the point where light rays converge to form a sharp image of an object to the digital sensor or 35mm film at the focal plane in the camera. The focal length of a lens is determined when the lens is focused at infinity.
Answer:
Focal length is a well known word in optical physics. Focal length is distance over which the parallel rays either converge or diverge.
For convex lens the focal length is positive. On the other hand, the focal length of concave lens is negative.
Thus, for convex lens, the focal length is a distance over which all the parallel rays will converge. A certain point over that distance all the parallel rays will converge, that point is known as focal point.
Similarly, for concave lens, the focal length is a distance where the parallel rays will diverge.
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