Sigma USB Dock Review

I review the Sigma USB dock. Just how much impact does this little thing have on the performance of your lens? Intro Music by WolfsteR.    / xxmarksomexx   http://audiojungle.net/user/WolfsteR _____________ Royalty-free music I'm using for my videos (2 months FREE if you sign up using my link!): https://artlist.io/artlist-70446/?art... You can also license stock footage from Artgrid.io (same 2 bonus months applies!): https://artgrid.io/Artgrid-114820/?ar...