Abstract

Four Cooke triplet systems have been designed for an 85-mm focal length and f/2.8 relative aperture for use as a 35-mm slide projector objective. Two designs use the existing glasses. In the other two designs the EDF glass of the negative lens was replaced by hypothetical low-index high-dispersion glasses. The performance of the triplet systems is found to improve considerably by using low-index high-dispersion glasses for the middle negative lens.

© 1982 Optical Society of America

Significance of selection of Petzval curvature in triplet design

K. D. Sharma and S. V. Rama Gopal
Appl. Opt. 21(24) 4439-4442 (1982)

Some infrared materials for the Cooke triplet design for the 3–5-μm spectral region: a comparison

K. D. Sharma
Appl. Opt. 31(1) 101-105 (1992)

Four-element lens systems of the Cooke Triplet family: designs

K. D. Sharma
Appl. Opt. 19(5) 698-701 (1980)

Design of a new five-element Cooke triplet derivative

K. D. Sharma
Appl. Opt. 18(23) 3933-3937 (1979)

Better lens for 35-mm cinematograph projector

K. D. Sharma
Appl. Opt. 21(24) 4443-4445 (1982)