The Series II Cooke Speed Panchros for cinematography were distributed exclusively through Bell & Howell in London and Chicago. The Series II lenses were developed for higher definition in wide screen presentations and to cover standard format 0.723 x 0.980 inches. By 1945 they came in focal lengths: 18, 25, 32, 40, 50 and 75mm. The 100mm, f/2.5 Deep Field Panchro was released in 1946.

The consumer market was also gaining momentum:

Portion of testimonial advert that appeared
in Life Magazine July 26, 1937.

"George Eastman [of Eastman Kodak] told WT [William Taylor of Taylor, Taylor and Hobson] that 90 percent of the 16mm film used in America passed behind lenses made in Leicester." (The Life and Times of William Taylor, page 74. Written and privately published by Harry Dagnall.) This quote dates back to the early 1930s but George Eastman’s statement proved true through at least the 1950s. The popular Bell & Howell Eyemo cameras used for newsgathering, documentaries and by the armed forces during World War II came supplied with Cooke lenses, as did the Bell & Howell 8mm Filmo camera for home movies.

1940s Ansel Adams

In 1932, Horace W. Lee patented (British patent 376,044) the Cooke Series XV Triple Convertible, which provided three focal lengths, with each half comprising two cemented doublets. The components gave excellent performance throughout the various focal length combinations.

Ansel Adams, famous American landscape photographer, shot many of his most famous images using this lens, as documented in his book "Examples: The Making of 40 Photographs." He appeared on BBC-TV stating that he used a convertible lens for many of his photos, then said, almost as a throw-away line, "A Cooke of course." This lens was made between 1935 through about 1962. The Series XV lens is difficult to find on the used market today, but is still sought-after by 8x10 inch format photographers due to it exemplary performance.

1944 Process Lenses

Cooke Process Lenses and Process Prisms helped expert cartographers and photographers provide the armed services with maps and charts of every description during World War II. Cooke process lenses were made from 1921 and were the first Apochromatic Process Lenses of British design. By 1947, three-quarters of the photo engravers in Great Britain and America were using them because of their uniformly keen definition.

By 1946, the Cooke name was associated with pioneering developments of large-aperture lenses for cinematography and television.