Patent
1980-04-30
1982-09-07
McGraw, Vincent P.
G02G 962, G02B 1302
Patent
active
043480845
ABSTRACT:
A tele-photographic lens of a small F-number comprising a positive first lens group, a negative second lens group, a negative third lens group and a positive fourth lens group. Focusing is carried out by moving the third lens group in the direction of the optical axis. Assuming that the compound focal length of the first, second and third lens groups is f(I, II, III), and the focal length of the whole system is fT, the lens satisfies the condition of 2 fT<f(I, II, III)<2.6 fT for correction of aberrations with the lens in a state of being focused on an object located at infinity.
REFERENCES:
patent: 4240703 (1980-12-01), Momiyama
Fujibayashi Kazuo
Kitagishi Nozomu
Canon Kabushiki Kaisha
McGraw Vincent P.
LandOfFree
Tele-photographic lens of large aperture 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 Tele-photographic lens of large aperture ratio, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Tele-photographic lens of large aperture ratio will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1339901