| 摘要 |
PURPOSE:To easily switch an average photometry and a partial photometry with a simple construction, by disposing a liquid crystal and photometric elements causing photodiffusion with the application of a voltage at the back of a pickup lens. CONSTITUTION:When no voltage is applied to electrodes 8b and 8c of a liquid crystal 8, a light passing through a pickup lens 1 and a half mirror 2 is collected on a photometric element 7 through a transparent liquid crystal 8 to achieve partial photometry neat a film f1. An AC voltage is applied to the electrodes 8b and 8c, then the liquid crystal 8 becomes photoscattering to achieve the average photometry for illuminance on film surfaces f2-f3. Thus, the switching of the average and partial photometry can easily be made with a simple constitution. |
