Telephoto lens system

A telephoto lens system comprising:

• (a) a first positive lens unit consisting of
• a first component which consists of, from the object side, a first positive lens element, a second and a third positive meniscus lens element having a convex surface to the object side;
• and
• a second component which comprises a fourth negative meniscus lens element having a convex surface to the object side;
• (b) a second negative lens unit including cemented elements with a positive and a negative lens element, the second lens unit alone moving in case of focusing, namely to the image side upon focusing from an infinite to a close distance;
• and
• (c) a third positive lens unit, wherein the telephoto lens system fulfills the following conditions:
• 0.15<r.sub.6 /r.sub.7 <0.85
• 0.0045f<d.sub.6 <0.0105f
• 0.85<f.sub.I-1 /.vertline.f.sub.I-2 .vertline.<1
• wherein,
• r.sub.6 represents the radius of curvature of the image side surface of the third lens element of the first lens unit;
• r.sub.7 represents the radius of curvature of the object side surface of the fourth lens element in the first lens unit;
• d.sub.6 represents the axial distance between the third and fourth lens elements in the first lens unit;
• f represents the whole focal length of the whole lens system when the lens system is in focus on an infinite object;
• f.sub.I-1 represents the compound focal length of the first component of the first lens unit, and
• f.sub.I-2 represents the compound focal length of the second component of the first lensunit.