ABSTRACT
Telephoto lenses consist of a front positive (F a) and a rear negative (F b) group separated by a distance T (see Figure 7.1). The telephoto ratio is defined as L/F (Cooke 1965). Assuming thin lenses, Telephoto lens groups. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315222295/bd2ad0d9-a48e-40ac-8986-c51474069cbd/content/fig7_1.tif"/> 1 F = 1 F a + 1 F b − T F a F b , https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315222295/bd2ad0d9-a48e-40ac-8986-c51474069cbd/content/eq83.tif"/> BFL = F ( F a − T ) F a . https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315222295/bd2ad0d9-a48e-40ac-8986-c51474069cbd/content/eq84.tif"/>
