A method of operating a three-dimensional image sensor may include: obtaining position information of an object using light emitted by a light source module, the three-dimensional image sensor including the light source module having a light source and a lens; and adjusting a relative position of the light source to the lens based on the obtained position information of the object. A method of operating an image sensor may include: obtaining position information of an object using light emitted by a light source module, the image sensor including the light source module; and adjusting an emission angle of the light emitted by the light source module based on the obtained position information.