Hello Don, There is the summary : F2 Photomic, F2S, F2SB : All non AI, AI and AIS lenses - fully meter coupled Series E and AF lenses - stop down metering only, as they have no prong T mount - stop down metering only F2A, F2AS : All AI, AIS, series E and AF leses - fully meter coupled All Non AI lenses - stop down metering only (with the coupling bit pushed up) T mount - stop down metering only Happy shooting, Sover