About the Leica APO-Telyt-R Module System
The APO-Telyt-R Module lenses are manual focus tele-photo lenses for
Leica-R single lens reflex cameras that have been corrected for
chromatic and spherical aberration using apochromatic lens elements.
The lens system is modular, which makes it highly unusual. There
are three focusing units and two heads available that can be
combined to obtain six different lenses with four focal lengths of
280mm, 400mm, 560mm, and 800mm. The 400mm and 560mm focal lengths
can be achieved in a faster (but heavier) and a slower (but lighter)
configuration. The different heads and focusing units are attached
to each other through a locking bayonet. All lenses have a slot for
Series-6 filter holders, so that Neutral Density filters or Circular
Polarizers can be used.
The modular system makes it possible to change focal length
without carrying a large number of heavy tele-photo lenses and offers a larger maximum aperture than corresponding
tele-zooms. Unlike tele-converters, modular lens systems do not
enlarge the central image circle and, hence, do not degrade the
image quality by magnifying lens flaws. Indeed, the Leica modular
lenses are themselves designed to be used with the camera maker's
1.4x or 2x APO-tele-converters.
The APO-Telyt system had been aimed at sport, bird and wildlife
photographers.
