I am a student photographer for my school, and many of my assignments include photographing guest speakers in dimly lit lecture halls. I recently purchased a used 70-200mm 2.8 IS II, I spoke extensively with the seller. He simply didn't find enough use for it, and it is in near-mint condition. I used it a few days ago for the first time in one of the lectures, and was the photos turned out nothing like what I'd expected from reading thousands of online reviews the past 5 months. The pictures were very soft and blurred sometimes due to a lower shutter speed...anything too high made them too dark, even at 2.8. I've heard that this lens can freeze sports motion at nighttime games, so I'm a little confused. Its very possible I'm just getting used to it, but I'm curious what your recommended settings would be for these circumstances, and if it's even an appropriate lens. I played with the ISO, but they got noisy if it was pushed too high. I am shooting with a 70D if that makes a difference. Any and all advice/info welcome..thank you!