QUOTE(kelvinyam @ Feb 26 2008, 06:10 PM)
Well said Albnok.
The point of bringing this up to clear up my doubts on people getting fast lens. A person like me who likes to shoot fauna (birds do not complain like human do btw), I like my image to be as sharp as possible.
When one purchase a 70-200mm F2.8, use it to shoot portrait is unlikely because there are better alternatives like super wide to wide and prime. So a lens like this will be used to shoot fauna or flora. So knowing a sharpest result can be obtained at F8 or F11, then what's the point of getting the F2.8 version?
I'm not saying that buying these lens is wrong, I'll just want to know the rational behind it. Smaller DOF and able to use it at dimmer condition don't quite justify, as the way I look at it.
I'm looking for something/answer that I do not know. So stop flaming me

Add on: I've just missed the point on shooting foot ball game (or what ever game). Still, I think 200mm will not give enough reach unless one is sitting next to the goal gate. This can be a reason for fast lens though, any other reason?
the 70-200 f2.8 is one helluva sharp lens, there is nothing wrong to use it to shoot portrait but yes, it is quite wasteful.
thats why i mentioned buying those lens give u more options to shoot different kidn of photos and the quality of the optics (sharp and less optics distortion) are well paid off.
talking about birdie, 70-200 is not quite enough anyway..lol
and for football sports, most of the ppl will use 400mm to 600mm
dun worry, kelvin, no hard feeling