Hello, you have come here looking for the meaning of the word focal length. In DICTIOUS you will not only get to know all the dictionary meanings for the word focal length, but we will also tell you about its etymology, its characteristics and you will know how to say focal length in singular and plural. Everything you need to know about the word focal length you have here. The definition of the word focal length will help you to be more precise and correct when speaking or writing your texts. Knowing the definition offocal length, as well as those of other words, enriches your vocabulary and provides you with more and better linguistic resources.
(optics) A measure of how strongly an optical system converges or diverges light, the inverse of optical power. In the simple case of a single convexlens, it is the distance along the optical axis from the principal plane of the lens to the lens's focal point (where, for instance, the film would be placed in a camera). For more complex or multi-element optical systems, focal length need not correspond to any obvious measurable physical distance.