Hi guys!I just want to ask for your suggestions as I am looking to get a zoom lens in the 70-200department. I'm looking at the 70-200 f4 IS and read lots of reviews that this lens is one of the sharpest in this focal length and even sharper than the f2.8 IS Mark I. Then came the f2.8 IS Mark II whichI think is a great lens but the price is a bit of an issue fora zoom. I'm still leaning towards the 70-200 f4 IS but I also like the f2.8 IS Mark II, either of the 2 lenses will complement my 24-105 f4 IS. Is the f2.8 ISMark II worth buying for the price orjust stick with the f4 IS? Thanks!