Hi. I have tried searching using the title as the search string and it returns a message saying (f4) is too short to search on. What the heck? Anyway. I'm starting to lust a little for something a little longer than my 80-200 2.8D. A 300 f4 is about a third the price of an f2.8. I've seen the killer f2.8 pictures people have posted on here and some of them just take your breath away. What's the image quality like between the two. Any samples from the f4? What would happen to an f4 with a TC1.7 on it?