| 释义 |
relative aperture
noun
: a measure of the angle of the cone of light rays from an object that traverse an optical system; specifically : the effective aperture of a camera lens expressed as a fraction of its focal length with the symbol f being used instead of 1 as the numerator or expressed as the ratio of the effective aperture to the focal length
< a lens having an effective aperture that is 1/45 of its focal length has a relative aperture of f/4.5 or 1:4.5 > |