Rod Details. The rods are the most numerous of the photoreceptors, some 120 million, and are the more sensitive than the cones. However, they are not sensitive to color. They are responsible for our dark-adapted, or scotopic, vision.The rods are incredibly efficient photoreceptors.owever, they are not sensitive to color. The 6 to 7 million cones provide the eye's color sensitivity and they are much more concentrated in the central yellow spot known as the macula. In the center of that region is the  fovea centralis , a 0.3 mm diameter rod-free area with very thin, densely packed cones.