Bright telephoto lens

Details Bright telephoto lens Bright telephoto lens

1984-10-19

1985-10-08

Corbin, John K.

G02B 1302

Patent

active

045456542

ABSTRACT:
A bright telephoto lens having a small telephoto ratio and with a properly compensated secondary spectrum which would otherwise largely affect the image-forming ability of the lens. The telephoto lens has a convergent lens group on the opposite side and a divergent lens group on the image side. The convergent group includes first, second and third positive lenses and a single negative lens, the first positive lens being closest to the object and made of an optical material having a partial dispersion ratio in the range of from 1.22 to 1.29 with respect to g-line and d-line. The negative lens is disposed more closely to the image than the first positive lens. The second and third positive lenses are disposed more closely toward the image than the first positive lens and are made of an optical material of anomalous dispersion having a partial dispersion ratio in the range of from 1.22 to 1.24 with respect to g-line and d-line, and have an Abbe number .nu..sub.d which ranges from 80 to 95.5. The telephoto lens satisfies the following relations: ##EQU1## where .psi..sub.1, .psi..sub.2, .psi..sub.3 are the refractive powers of the first, second and third positive lenses, respectively, .nu..sub.dn is the Abbe number of the negative lens, .psi..sub.p is the sum of the surface refractive powers of the three positive lenses on their image sides, and .psi..sub.n is the surface refractive power of the negative lens on the image side, with .psi..sub.n <0.

REFERENCES:
patent: 4113357 (1978-09-01), Nakamura
patent: 4293197 (1981-10-01), Kobayashi et al.

Affiliated with

Also associated with

Rating

Bright telephoto lens does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Bright telephoto lens, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bright telephoto lens will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2216640