I have a Nikon 70-200mm f/2.8, and I find it too short to shoot any birds in my backyard (and there are a lot of badass birds up here in Maine). So, I don't have the money to go for a long lens right now, so, I'm thinking of going with a Nikon teleconverter until I can afford a 200-400 f/4 or 300mm f/2.8 (with which I'd probably use a teleconverter with anyways sometimes). So, anyways, anyone here have experience with Nikon's teleconverters (I'd like to stick with Nikon, and not go 3rd party, just because I'm like that)? I'm looking at pretty much any of them right now, 1.4x, 1.7x, or 2x. And has anyone used those with the 70-200mm f/2.8 VR? Thanks.