Viewfinder for SLR camera - has both automatic and manual focussing, adjustable as required

摘要

An sLR camera with automatic focus has a manual override to provide special effects. The image is focussed on a matt screen formed by a liquid crystal plate which is normally transparent and changed matt by applying a control signal. The liq. crystal plate (5) is positioned along one face of the penta-prism (3) for optimum focus setting. A manual switch (8) inhibits the automatic focus control (7) and provides the matt signal to the liq. crystal plate. The signal can be a repetitive pattern to allow normal viewing as well as focus control.