Abstract: A detecting device comprising a projecting optical system for focusing the image of an object to be examined on a focusing glass, a plurality of photoelectric elements which can be set in proper positions on the focusing glass, circuits including level adjusting circuits and for converting outputs from the respective photoelectric elements to binary logical outputs and circuits for converting these binary logical inputs to octonary logical outputs so that the slightest variations of the shape and state of the object can be easily and accurately detected. The respective photoelectric elements can be moved out of the projecting light path as required. The projecting optical system consists of an objective lens system and a projecting lens system so that a magnified erecting image of the object can be obtained on the focusing glass.

Abstract: A variable aberration lens system usable not only as a general photographic lens but also a soft focus lens is provided. The variable aberration lens system includes at least a variable meniscus-shaped air space and cementing surface which are respectively concave against a stop provided therein. A very high resolving power and high contrast can be obtained when the variable aberration lens system is used as the general photographic lens, and a photograph in which an out focus image of the background or foreground is fine can be obtained by varying the width of the air space when the variable aberration lens system is used as the soft focus lens.