Thus, secondary spectrum becomes a serious problem as focal length increases. Lens designers are constantly at work to produce raw materials and new designs resulting in optical glass with lower refractive indexes and abnormally low dispersion. Both types provide images unusually free from chromatic aberration that often affects the performance of long focal length lenses. Reflex lens with mirror design does not have chromatic aberration and often used as a cheap high performance ED lens. Zuiko Reflex 500mm F8 Makes possible the interesting creative effects of the reflex type lens, while also affording fantastic compactness and portability in this powerful super telephoto length.
Image quality is constant even at close focus distances.
Internal coating on the barrel minimizes flare. Instead, a front mounting 72mm is used. I am not so sure whether it comes with the five color correction and neutral density filters which usually come with the package with such a lens. So, it is better to double check this especially when you intend to purchase a unit from any used outlet. As no photographer in the world would possess ALL the lenses within a single trade name.