ABSTRACT
A major grouping of viewfinder systems is that of the direct or direct vision type using a separate optical system from that used for camera image formation. The frame finder may be used separately from the camera when searching for the best viewpoint for a subject and choice of lens. A large version of the brilliant finder was used in the Voigtlander Brilliant camera of the 1930s, but with a small central area of ground glass for focusing purposes. The introduction in 1932 of the reflecting frame finder by van Albada largely overcame the errors of earlier types caused by out of focus frames and eye position changes. A director’s viewfinder as used in movie and video production is a direct vision viewfinder typically with a 12:1 zoom ratio plus wide-angle and anamorphic attachments. Addition of external afocal converters to change focal length alters viewfinder coverage appropriately by associated supplementary elements placed over the finder objective.
