An imaging apparatus including a light source is provided. The imaging apparatus includes a light-emitting device and a photoelectric conversion device in a pixel, and a pixel circuit has a function of outputting third data generated by multiplying obtained first data by second data (weight). Calculating the third data externally enables more detailed information on a subject with respect to a specific wavelength to be obtained. In addition, reading out collectively a plurality of pixels to which proper weight is given enables output of difference data between pixels and the like, which allows external calculation to be omitted.