Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
PHOTOGRAPHIC LENS SYSTEM
Document Type and Number:
Japanese Patent JPH11125767
Kind Code:
A
Abstract:

To obtain the small-sized, low-cost photographic lens system which has high performance, long back focus, and excellent telecentricity.

This system is equipped with a 1st lens group 10 with negative refracting power, a stop S, and a 2nd lens group 2b with positive refracting power in order from the object side and the 2nd lens group 2b consists of a positive meniscus lens 21 having a convex surface on the image side, a cladding lens of a positive lens 22 and a negative lens 23, and a positive single lens 24 and satisfies the inequalities (1) to (4) (l) 1.5<f1/f<5.0 (2) 1.1<f2/f<2.0 (3) 0.6<DAS/f2<1.2, where (f) is the focal length of the whole system, f1 the focal length of the 1st lens group, f2 the focal length of the 2nd lens group, and DAS the distance from the stop to the 1st principal point of the 2nd lens group.


Inventors:
OZAKI HIROYASU
Application Number:
JP28833397A
Publication Date:
May 11, 1999
Filing Date:
October 21, 1997
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
ASAHI OPTICAL CO LTD
International Classes:
G02B9/10; G02B13/04; G02B13/18; (IPC1-7): G02B13/04; G02B13/18
Attorney, Agent or Firm:
Kunio Miura