Kevin,
Agree with most of what your wrote. Where I disagree is on the lenses that will work with the D800 series. While there is no question that newer, more expensive lenses have better specs, the question is how much difference can you actually see.
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www.moosepeterson.com]
I was fortunate to have known and become friends with some of the most well-known railroad photographers...Dick Kindig, Otto Perry, Bob Richardson, Jack Thode, and others. Some had the best pro quality equipment and some had semi-pro or even amateur equipment. I have made prints from the film of most of these guys and while all the images were historic and I was lucky to be able to have access to them, there was a difference in photo quality.
An Air Force fighter pilot once told me that the Russian MIGS often had better specs than our fighters but most of the time they lost because our guys were better.