1. A camera provided with an exposure arithmetic apparatus, wherein said exposure arithmetic apparatus comprises: a light amount measuring device for measuring an amount of light for each of a plurality of segmental zones in a field; a pattern generating device for generating a plurality of patterns for spatially pattern-classifying said field; a correlation arithmetic device for calculating correlation values, each representing a degree of correlation of said each pattern with said field, based on outputs from said light amount measuring device and said pattern generating device; a pattern luminance calculating device for performing an arithmetic process based on the output from said pattern generating device, of the output from said light amount measuring device; and an exposure arithmetic device for performing an arithmetic operation of correct exposure, based on outputs from said correlation arithmetic device and said pattern luminance calculating device.