"Brand new to photography, or brushing up on some of the basics? Dont be shy! " Haha, I'm holding nothing back! Here we go... Please tell me if my questions make no sense, or if I' m just missing something. :lmao: 1/ What is the difference between ring / micromotor USM? 2/ What on earth is the crop factor, and how does it affect how I shoot photos? (or how lenses work..."effective focal lengths..?" I read a bit, and there just seems to be a lot of flame fests and I understand nothing haha) 3/ In what situations besides taking photos of fast moving things would you want higher shutter speed? ie what benefits are there which I'm not aware of? 4/ a) how does a camera autofocus? IF it does so by changing the fstop...focal length and aperature THEN: b) how do prime lenses autofocus? :/ 5/ What is ISO? Happy for a technical explanation, and how is GRAIN generated at higher ISOs.