The ratio of image to object size in an optical system. may be real (linear) or apparent (angular). milliradian (mrad)1/1000th of a radian, or 0.0573 degrees; the angle whose tangent is 0.001.
The increase in the apparent or perceived size or subtended angle of an image in relation to actual size of object.
Magnification ratio, английский The ratio between the focal length of a lens and the focal length of a standard angle lens. indicates the magnification of the image when compared to an image from a standard angle lens.