I have compared my output images with the Nikkor 200-500 f/5.6 to the 500mm f/4 and for the life of me I cannot see a $9,000 difference especially when you have to add the 1.4 extender to get to 700mm and thus lose that stop. Other than better weatherproofing, I frankly can't see the sense in this purchase because unlike going from a Nikkor to a Zeiss, there just isn't that much of a quality jump.
Anyone else's thoughts on this?