Solid state imaging apparatus and imaging system using the same

An imaging system comprising a solid state imaging apparatus, said solid state imaging apparatus comprising:

• a pixel array in which pixels arrayed in a matrix shape, with each pixel having a color filter of one color, and including a plurality of photodiodes each of which receives an incident light passing through the color filter;
• and
• an adding circuit, wherein
• the pixels include a first pixel, a second pixel and a third pixel,
• each of the first pixel, the second pixel, and the third pixel has a color filter of a first color, and
• the adding circuit performs addition of (i) a signal based on an output of only a part of the plurality of photodiodes of the first pixel, (ii) a signal based on an output of the plurality of photodiodes of the second pixel, and (iii) a signal based on an output of only a part of the plurality of photodiodes of the third pixel;
• an optical system that forms an image on the plurality of pixels;
• and
• a signal processing unit that processes a signal output from the solid state imaging apparatus and generates image data.