Comparing the RCD on my (silver) F model with that on the (silver) T model, the F dial has apparently been "beefed up" - it looks metalic and large, rather than black plastic and smaller as it is on my T. Importantly, the detentes on the F model are definitely more robust, and it takes greater pressure on the dial to spin it when changing a Q menu item setting. Although I don't usually use the Q menu (too many items to memorize, and hidden visual cues about alternative settings), I can see how the new RCD on the F would result in an accidental activation of a setting.
