I am glad to tell you that , Yes we can use manual focus while video recording.turn the dial to M mode,and press macro button,select MF, start video recording then use menu ring and roll it... wow !!!! That's all i was expecting from this massive camera... Anyway Thank you Mr. Ben.....
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You can also use the side lens "zoom/focus" rocker (if assigned in the menus) to manual focus in video mode as well.