Hi!
I want to buy tele lens mainly for wildlife, zoos, birds etc
what focal lengh am I after? I think its around 500
but considering my DX sensor, that's about 300-350

I have Nikon D80
budget is less than 1500
so
I'm thinking about 2 options currently
1) Nikkor 70-300mm f/4.5-5.6G VR
2) Sigma APO 120-400mm f/4.5-5.6 DG OS HSM
3) Some other Sigma or Tamrons

thoughts?