Thanks for the response Neuro.. i actually was just beginning to think that! With the 5d MK III i could've just bought the 70-200 f/4 L IS and just push the ISO higher for indoor scenes (church wedding, receptions, general indoor scenes, etc)..AND save almost $900!
Im starting to rethink this decision of mine in buying the 70-200 f/2.8 IS II ?!?? grrrrr... Anyone else out there think that returning the 70-200 2.8 IS II and getting the70-200mm f/4 IS is a better idea since im using the 5D MK III??
Sometimes it's better to have the extra capability in reserve. I occasionally find myself shooting at ISO 6400 with a 5D II at f/2.8 or wider at slow shutter speeds (1/30s).
How often would you shoot at f/2.8? For single subject sports, I use f/2.8 a lot. For portraits, f/4-f/5.6 is more common especially with multiple subjects. If you decide you don't need the f/2.8 then switching to f/4 makes sense.