Originally posted by Pål Jensen Yes, Pentax used one of their telescope designs and converted it to a SLR lens in order to save developing cost. Perhaps cooperation with Tokina could be a solution for future long lenses?
In spite of the 560 shortcomings, it is half the weight of the FA* 600/4 and probably 1/3 of the price of a hypothetical brand new D-FA* 600/4...
Cooperation with Tokina is no longer an option IMO; particularly not on such expensive lenses.
I guess the DA 560mm was the best they could do given the circumstances, and even so it was canceled (Hoya ownership - Ricoh resurrected the project and made it happen).
Under different circumstances they might've tried a classic telephoto design... would they try it now? Given what they did for the D FA* 85mm I'd say this is possible... not sure if likely though.
OTOH it seems the 560mm has some unique qualities, if we listen e.g. to Chris Mak (who owned the lens for a while).