I'm contemplating whether or not to wait for the as yet to be released Fuji 200mm F2.0 in 2018 sometime or go with the 100-400. My question is since the 100-400 has OIS, shooting indoors should be fine at 4.5 and a minimum shutter speed of say 60? My guess is the 200mm will Not have OIS so even though it's a fast lens, you're still going to have to bump the shutter speed up there which would negate any advantage it had over the 100-400 anyway. Or maybe I'm not thinking correctly here? I've owned a Pentax fast 200mm F2.8 so I know what it's limitations are. I would normally shoot at least 4.0 indoors with shutter speed of 200 and ISO 2500, but my Pentax body has image stabilization. Fuji does not. Since I want this lens to be used not only for occasional, again "occasional" indoor shots and the remainder fast sporting events outdoors that maybe the 100-400 might be the way to go. Yea I know the size will be gargantuan compared to the 200mm but I'm willing to sacrifice that. My current set up is the Fuji X-T1 along with the 14mm, 27mm, and 90mm prime lenses.