Ricoh has a patent (P2018-224783) for what appears to be a new Pentax DFA 70-300mm f/4.5-5.6 SR or similar: Focal length: 72.2 135.0 193.2 F value: 4.43 4.88 53.4 Back focus: 38.3185 49.5751 57.6036 Seven different lens designs are described in the patent with apertures ranging between: f/4.43 and f/4.63 at the shortest focal distance … Continue reading Pentax DFA 70-300mm f/4.5-5.6 SR lens patent