PURPOSE: To obtain a photographic lens system which is well corrected in both of sagital astigmatism and meridional coma aberration at an intermediate angle of view and the max. angle of view by using glass having high refractive index for all of three elements of the lenses of a lens system of three elements in three groups and specifying the specific elements thereof.

CONSTITUTION: The elements of the lens system which consists of the lenses of three elements in three group; a positive first lens 11, a negative second lens 12 and a positive third lens 13, successively from an object side and is arranged with a diaphragm behind the third lens are set as follows: (1) 1.6<f/f1<1.93, (2) 1.80<N1, (3) 1.78<N3<N1, (4) 1.73<N2<N3, (5) 1.73<N2<N1, where f: the focal length of the entire optical system, f1: the focal length of the first positive lens group. N1: refractive index of (d) ray of the i-th lens (i=1, 2, 3). The F-number of this rear diaphragm type triplet lens system consisting of three elements of the lenses is 3, 5, the angle of view is 65 to 67 and the telephoto ratio is ≤1.05. Miniaturization is thus attained.