I have just started to take movies of birds at my feeders with my Nikon D850. My purpose is to get some short videos to email to friends. My test videos were taken at the default setting and the file size was huge and I could not send it. What settings do you recommend to produce smaller file sizes? Are Mp4 videos smaller than MOV videos? This is my first attempt at taking videos on any Nikon body. I have a D800e and D 810 and D500 too.