I'll have to second Arcaxis' last paragraph On camera microphones--even high quality shotguns--rarely give very good sound quality on anything beyond a bit of location atmosphere.
Other, better options are things like putting your shotgun on a fishpole and have somebody else get the mic (in a suitable windscreen) as close to the subject of your video as it can get and stay out of frame. Or clip on radio mics are very commonly used.
Or--as a last resort--do some ADR (dialogue replacement) in the studio after the edit FYI, it's not uncommon for more than 80% of film dialogue to be handled this way,
Anyway, some things to think about before committing to an expensive camera mount mic.