Super wide angel lens system using an aspherical lens

A retrofocus type super wide angle lens system comprising a front lens group of negative power and a rear lens group of positive power, arranged in this order from an object side, wherein said front lens group comprises a negative meniscus first lens element having a convex surface facing said object side and a second lens element having at least one aspherical surface, arranged in this order from said object side, said second lens element being shaped so as to form a biconcave lens in a vicinity of the optical axis of said second lens element and to form a negative meniscus lens having a convex surface facing said object side at a peripheral portion;

• wherein said front lens group comprises a negative meniscus first lens element having a convex surface facing said object side and a second lens element having at least one aspherical surface, arranged in this order from said object side, said rear lens group comprising a positive single third lens, a diaphragm, a cemented lens assembly having a negative fourth lens element and a positive fifth lens element cemented thereto, and another cemented lens assembly having a negative sixth lens element and a positive seventh lens element cemented thereto, said optical elements being arranged in this order from said object side, and wherein said lens system satisfies the following conditions:
• 2.50.ltoreq.R.sub.8 /f.ltoreq.3.10
• 2.35.ltoreq.R.sub.11 /f.ltoreq.2.55
• 14.ltoreq.f.sub.7-9
• 4.ltoreq.f.sub.10-12 .ltoreq.5
• wherein
• R.sub.8 represents a radius of curvature of the surface of said fourth lens element on said image side,
• R.sub.11 represents a radius of curvature of the surface of said sixth lens element on said image side,
• f.sub.7-9 represents a resultant focal length of said fourth and fifth lens elements,
• f.sub.10-12 represents a resultant focal length of said sixth and seventh lens elements, and
• f represents a focal length of the entire lens system.