Telephotographic lens system having short total length

A telephotographic lens system comprising a first positive meniscus lens component, a second positive meniscus lens component, a third negative meniscus lens component and a fourth positive cemented lens component, and said lens system satisfying the following conditions:

• (1) 0.4f <
• f.sub.12 <
• 0.5f
• (2) 4 <
• f.sub.123 /f.sub.45 <
• 6
• (3) 0.28f <
• r.sub.3 <
• 0.35f
• (4) 0.6f <
• r.sub.4 <
• 0.75f
• (5) 1.4f <
• r.sub.5 <
• 2f
• (6) 0.18f <
• r.sub.6 <
• 0.24f
• (7) 0.98 <
• .vertline.r.sub.6 /r.sub.8 .vertline. <
• 1.03
• (8) 1.3f <
• r.sub.7 <
• 1.8f
• (9) 1.68 <
• n.sub.1 , n.sub.4
• 1.6 <
• n.sub.2
• (10) 1.05 <
• n.sub.4 /n.sub.5
• (11) 10 <
• .nu..sub.5 - .nu..sub.4
• (12) 45 <
• .nu..sub.1, .nu..sub.2
• .nu..sub.3 <
• 28
• wherein the reference symbol f represent the focal length of the entire lens system, the reference symbol f.sub.12 designates the total focal length of the first and second lens components, the reference symbol f.sub.123 denotes the total focal length of the first through the third lens components, the reference symbol f.sub.45 represents the focal length of the fourth lens component, the reference symbols r.sub.3 through r.sub.8 designate radii of curvature on the surfaces of the second and third lens components as well as object side surface and cemented surface of the fourth lens component, the reference symbols n.sub.1, n.sub.2, n.sub.4 and n.sub.5 denote refractive indices of the first and second lens components as well as the two lens elements of the fourth lens component, and the reference symbols .nu..sub.1 through .nu..sub.5 represent Abbe's numbers of respective lens elements.