connected to non inverting inputs of operational amplifiers a1 a2 and a4 the inverting input of the amplifier a1 is connected to the ground through a constant current source 52 and is also connected to the output thereof through a semi fixed resistor rv1 which operates to adjust the reference voltage vref for purpose of introducing a variety of photographing information connected between the output and the non inverting input of the amplifier a1 are a variable resistor rv4 which is used to introduce an exposure correction value cv a variable resistor rv5 which is used to introduce a film speed value sv and a variable resistor rv6 which is used to introduce an aperture value av in parallel relationship with each other movable sliders on these variable resistors rv4 to rv6 are connected to individual inputs of a multiplexer 53 which is formed by a plurality of analog switches the inverting input of the amplifier a2 is connected to the ground through a semi fixed resistor rv2 which is used to adjust a brightness value bv of an object being photographed which is determined by the spotwise photometry and is also connected to the collector of a pnp transistor q1 the transistor q1 has its emitter connected to the output of the amplifier a2 and its base connected to the non inverting input of the amplifier a2 the output of the amplifier a2 is also connected to the emitter of a pnp transistor q2 the collector and.