Kronie wrote in post #10137457
I just bought a 70-200 MK II to replace a 70-200 F4 and ended up sending the MK II back. Its a beast and heavier than my 100-400. It also no sharper than my F4 L IS. For portrait work below F4 I have a 100L. The reality is that F4 for portraits... at least on a full frame camera is just fine. The DOF @ F4 is very thin anyway, especially at 200mm.
Unless you just have to have 2.8 for low light or where you cant use a flash, than save the money and the weight and get the F4 version.
looks like i missed out on some details ... i will use an FF cam for portraits.
nightcat wrote in post #10137588
Why would you use anything but your 100mm 2.8 for portraits? If you want the best, you already have it with this extremely sharp lens. So, if you drop $2500 on the new 2.8 zoom, you'll get what you already have... great sharpness at 2.8! To answer your other question, what would I rather have, the new zoom or the 200mm 2.0 if they were the same price? I would
MUCH rather have the spectacular 200mm 2.0 as its the most incredible lens Canon makes.
And finally, you say you wouldn't be interested in the great 135mm 2.0. Why not? If you want great outdoor portraits, this is your lens, and its a fraction of the cost of the great 200mm 2.0. If you really want a slight improvement for portraits over your excellent 100mm macro, I'd buy the very fast and sharp and light 135mm 2.0 and save for a later purchase of your dream lens, the 200mm 2.0.
because i heard that the compression on 200mm would be great for portraits 
plus of course, the versatility of the zoom (i think the 70 side should be wide enough for most uses)
i'm still wishing for a 135 f2 IS 
peter.pan wrote in post #10137721
If you have the 100 f/2.8L IS and the 85 f/1.8, just use them for portraits and if you still need a tele-zoom get the 70-200 f/4 IS. Personally I like Sigma 50 f/1.4 (Sigmalux) for portraits on a crop frame camera.
since 100 is my longest FL, if any occasion comes up, i won't have a telephoto in my kit (believe me, the nifty two fifty is haunting me, but i keep thinking that i don't want to buy the 250 and will only "settle" for the f4 IS. then if im thinking about the f4, i might as well think about the 2.8.)
main usage would also be indoors, mostly nighttime, ambient light