input to the light metering circuit 2 the light metering circuit 2 converts each light metering output into a luminance value bv i by the use of a fully open f value signal f o not shown of the photo taking lens 4 and outputs it to the exposure calculating means 13 the exposure calculating means 13 receives the output of the split metering means 3 and the output of the focusing state classifying means 12 calculates proper exposure b in accordance with an algorithm which will be described later with reference to fig5 and outputs it to exposure control means 14 in response to this output the exposure control means 14 controls an aperture 15 and a shutter 16 the positional relations between the central areas 1a 1c of the light metering photoelectric conversion element 1 and the photoelectric conversion element group 7 of the focus detection means 9 will now be described with reference to fig2 b and 3c as shown in fig2 the lengthwise widths of the central areas 1a 1c of the light metering photoelectric conversion element 1 are set to the substantially the same as the lengthwise width of the photoelectric conversion element group 7 further as shown in fig3 b and 3c areas a1 and a2 occupying the left one third of the photoelectric conversion element group 7 are disposed correspondingly to the light metering area 1a at the left of the central portion areas a3 and a4 occupying the central one third of the photoelectric conversion element group 7 are disposed correspondingly to the central light metering area 1b of the central portion and areas a5 and a6 occupying the right.