Nikon 70-200 2.8 with a TC2.0 VIII is not very good on my D800

How would that be any different than using the D800 at a given print size or display resolution?  This is the same argument as the idea that the d700 is somehow better at high ISO because 100% crops look better from it (even though they're 1/3 as much information).  Just because the effects aren't as noticeable at native resolution on a D700 doesn't make it somehow a better camera to use with this combo.

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-Mike