METHOD FOR CONTROLLING DIAPHRAGM IN AF SYSTEM

摘要

PURPOSE:To prevent exposure at the time of flash photographing from the generation of errors by determining a stop value in each zone based on a distance up to an object when the quantity of light in an intermediate level is obtained from the object having a reference reflection factor. CONSTITUTION:The diaphragm value of each zone at the time of flash photographing is determined based on the distance up to the object when the quantity of light in the intermediate level between the upper and lower limits of each zone is obtained from the object having the reference reflection factor. When T1-T2 zones are decided for instance, the diaphragm value is determined based on the distance Xs corresponding to an intersecting point M2 between the intermediate level of the T1 and T2 levels and a curve M. The diaphragm value at that time is a value obtained by dividing the distance Xs by the guide number of a strobe. Even if the quantity of reflected light from the object is slightly deflected to the upper or lower side, the exposure error is not so increased and flash photographing can be attained.