If you could have only one...

[Fatalv]

I was looking at a TEC 140 before I starting thinking the camera lens route. I figured at around $7k-$8k for a full TEC setup why not look into a big white and be able to use it for terrestrial work

Just for a pause here, but you do realize that all of the Canon VII lenses are significantly above this dollar range at MSRP, correct?

Yes, I'm aware of the price difference. I've been looking at both CPW Street Price and Adorama. With the recent price drops the big whites have come down some. Currently the 500 f/4 @ $8.35k CPW which is fairly in the league of the TEC.

 

[ktatty]

I have the 400 2.8 because i need the 2.8 for field sports at night on a full frame. For birds i use the 1.4 ext- or a crop body w/o extender. I would go with the 500 f/4 if I didn't need the 2.8- the weight difference between the two makes the 500 easier to move around with( i still need a monopod) and you have more reach for birds. The weight difference on paper doesn't seem like much, but it is quite a difference when handling the two.