Al’s advise is right on the money: understand your craft.
Also, PLEASE do not learn to rely on auto-focus for your video work. Train your eye / hand and get used to the focal qualities of the glass you DO own. If nothing else, get an eye-loupe for your monitor to scrutinize the focus of your image and understand the depth of field effects. When you can get used to working in low f-stops and still holding focus, you are entering the league of giants.
Rock ON with your bad self!
Best Regards,
Lars Elling Lunde
Lundegaard Imageforge
(845) 915-4048 – lars@lundegaard.com