Modern Lens Design, 2nd Edition

Chapter 21Projection TV Lenses and Macro Lenses

21.1 Projection TV Lenses

The lenses used to project large-screen television must have a high speed (usually f/1 or faster) to project a bright enough image, and must also cover a relatively wide field to produce a large picture in a short throw. However, they do not need to be fully chromatically corrected, since the three color images are independently projected and each lens covers only a limited spectral band. The resolution requirements are relatively modest, in keeping with the low resolution of television, but, of course, a high modulation transfer function (MTF) is needed to maintain the image quality at this low resolution. Plastic elements are used for low cost and light weight, and (primarily) ...