[Chez]

Right, I'm pretty much at a stage where I have everything I want/need with one huge exception... a fast super telephoto lens.

I have the 70-200mm VR and 1.7x TC, which gets me to 340mm, but this just isn't enough sometimes.

I also have a Bigma (Sigma 50-500mm), but this is f/6.3 at 500mm..

My thinking is that if I get an F2.8 300mm lens, I can use a TC to get either 420mm f/4, 510mm f/4.8 or 600mm f/5.6

So, my options are -

Sigma 120-300mm F2.8
Nikon 300mm F2.8 (second hand)
Nikon 400mm F2.8 (second hand)

I have included the 400mm as I have found a second hand example for £1600, however at over 6kg I don't think this is a sensible option.

Are there any other obvious alternatives (I have ruled out the Sigma 300mm as I believe the 120-300mm is based on this and offers a zoom?)?

I would ideally like the Nikon 300mm F2.8 VR, but it is a bit too much for my wallet and I haven't seen any second hand ones around..

Any thought/advice welcomed.

Thanks
Chez