This has been torturing me for the last week. I need image stabilization plain and simple. I just want that tiny bit of sharpness that I am not getting all the time to boost my perfect pile up a little more. I am at about 75p% keeper rate and 15% perfect but thats not acceptable. Move the keeper to 85% and the perfect to atleast 25% we are in business. Mono pod would solve the problem with my current lens (Sigma 70-200 hsm VII). I know this because I tried the monopod and it worked. But I hate using a monopod for MX. So the question is f2.8 IS or F4 IS? I don't care about weight or length or price. Not willing to put the money down on a f2.8 IS II not worth it to me. I shoot with a 1d3 currently. I do shoot indoor but not a lot. Give me your feedback and comments.