Got my rented 70-200mm F4L IS yesterday. Nice sharp lens. This was taken with only the UV filter they sent on the lens. I didn't have time to dig out and mount the CPL, even though with the haze, it needed it. The second shot is a 100% crop from the first. Pretty sharp lens. I'm still not convinced this would work better for me than a 135 F2L, though. But I have the rest of the week rental period to get used to it.