Hello,
Thanks for the feedback, I'll will have our answer changed to reduce any confusion.
Per
us.ricoh-imaging.com, the weather-resistant HD PENTAX-DA 55-300mm F4.5-6.3ED PLM WR RE telephoto zoom lens is designed for use with PENTAX K-mount digital single-lens reflex (SLR) cameras.
The new electromagnetic diaphragm control system designed for quiet sound operation during movie recording when mounted on the new PENTAX K-70 digital SLR camera body.
Ricoh/Pentax adds: This lens features a KAF4 lens mount compatible with an electromagnetic diaphragm control system. In order to use this lens, the camera’s firmware must be upgraded to the latest version (except for the PENTAX K-70). If this lens is mounted on a camera without proper firmware upgrade, its diaphragm control mechanism becomes inactive, making it impossible to obtain correct exposure.
Cameras compatible with this system: PENTAX K-70, K-1, K-3 II, K-S2 and K-S1
I called Ricoh Support and they said if the lens is used on other/older bodies, full auto exposure may not work accurately [the reps words to myself]. He added they are unaware of issues with the lens used in manual mode or aperture priority.
Chuck