Abstract: A number of light receiving elements are used for measuring the brightness Bi of a number of parts of the scene and the maximum brightness Bmax and the minimum brightness Bmin are detected among the measured brightness values. Then, the scene brightness B is calculated by use of a formula: ##EQU1## Based on the scene brightness thus obtained, the aperture or shutter is controlled to obtain appropriate exposure. In case where the weighting coefficients for the number of light receiving elements are made equal to each other, the average brightness Bmean throughout the whole image is used.

Abstract: In a camera or a printer, exposure is controlled based on a selected mode of light measuring means which has a number of different modes of weighting for differently weighting various parts of an image in light measurement. In the light measuring means, there are provided a number of image information operating means which have different ways of weighting various parts of an image. The weighting mode is properly selected according to the kind of the scene of the image. The light measuring means comprises a number of photodetectors arranged in the form of arrays and a number of operating means for weighting the outputs of the photodetectors in different ways.

Abstract: Red, green and blue densities of a color negative are measured at a plurality of points thereon. The measured densities are normalized by a normalizing circuit so that the same levels of density signals can be obtained regardless of the gamma value and sensitivity of the negatives when the same subject matter is photographed under the same conditions. The normalized density signals are plotted in a chromaticity coordinate system and examined as to whether or not they fall within a given region defining a particular color in the chromaticity coordinate system. When the level of the normalized signals with respect to a given point falls within the given region, the point is determined to have the particular color defined by the region in the chromaticity coordinate system. When the color negative includes a predetermined number of points of the particular color, the exposure in a color printer is controlled to reproduce the particular color in a desirable condition.

Abstract: An improved method for controlling the quantity of exposure in photographic printing to obtain high-quality prints is disclosed. The method is carried out by photoelectrically detecting a plurality of optical densities from a principal portion of a negative film then discriminating the maximum value and the minimum value of the photoelectrically detected optical densities. The difference between the maximum and minimum values is calculated to achieve a first output, and the first output is non-linearly converted and combined with the maximum or minimum value output to achieve a third output for controlling the quantity of exposure. The method provides satisfactory prints even from those negative films having principal subject density failures or color failures.