A not quite symmetrical wide angle embodiment of a double Gaussian formulation. In a largely successful attempt to minimize vignetting so characteristic of wide angle 35mm lenses the rear element is very noticeably larger than the front. (Turned around and focussed at infinity, a recalculation of lens parameters would yield closer to f1.4 !) The lens exhibits extremely low distortion, excellent color reproduction and extraordinarily high image quality. The 7/5 formulation would argue that is is not a classical Gaussion in the true sense but the mild plus element just to image side of the center of the lens assists in the success of the asymmetrical formulation.

BTW, it really is a 7/5 formula; the 2nd and 4th groups are actually split cemented pairs but poorly characterized as such in the diagram supplied by Kyocera/Contax.