Patent
1980-02-27
1981-10-06
Clark, Conrad J.
G02B 1302
Patent
active
042931975
ABSTRACT:
A high performance telephoto lens having a small telephoto ratio including eight lenses disposed in seven lens groups in front, intermediate and rear groups. The front lens group is composed of, in order, a positive lens having two curved surfaces with the surface of greater absolute value of curvature disposed on the object side, a positive meniscus lens having its convex surface disposed toward the object, a negative biconcave lens having the surface of greater absolute value of curvature disposed toward the image side, a positive meniscus lens having a convex surface directed toward the object. The intermediate lens groups includes two cemented lenses one of which is a negative biconcave lens disposed on the object side and a positive lens disposed on the image side. The rear lens group is composed of a negative lens with the surface of greater absolute value of curvature disposed on the object side and a positive convex lens with the surface of greater absolute value of curvature disposed on the image side. The lenses satisfy: -1.2<(r.sub.6 +r.sub.5)/(r.sub.6 -r.sub.5)<-0.7, 6.7<.vertline.f/r.sub.9 .vertline.<7.6, and - 0.5<f(-1/r.sub.14 +1/r.sub.15)<3, where r.sub.i is the radius of curvature of the i-th lens surface and f is the overall focal length.
REFERENCES:
patent: 4113357 (1978-09-01), Nakamura
Kobayashi Koichi
Okudaira Sadao
Asahi Kogaku Kogyo Kabushiki Kaisha
Clark Conrad J.
LandOfFree
Telephoto lens with small telephoto ratio does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Telephoto lens with small telephoto ratio, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Telephoto lens with small telephoto ratio will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1203665