Color vision are mixed together or diluted with white light, the number of distinguishable chromaticities can be quite high. In very low light levels, vision is scotopic: light is detected by rod cells of the retina. Rods are maximally sensitive to wavelengths near 500 nm, and play little, if any, role in colour vision. In brighter light, such as daylight, vision is photopic: light is detected by cone cells which are responsible for colour vision. Cones are sensitive to a range of wavelengths, but are most sensitive to wavelengths near 555 nm. Between these regions, mesopic vision comes into play and both
Kodak Retina Ausf. II Retina IIc, which is later mounted on the Type 019 Ausf. II Retina IB and Type 028 Retina IIIC. The second generation Type 034 Retina Reflex S of 1959 shared "S" type lenses with the Type 027 Retina IIIS (below), and offered fully coupled metering. With these the entire lens detached allowing for a wider range of focal lengths, 28mm to 200mm. At this point economical Japanese SLRs were becoming available and the Nikon F of 1959 would set the standard for future camera system. The Reflex III of 1961 and Reflex IV of 1964 brought minor improvements