[Beagleone]

Nikon has a 80-400mm f/4.5 lens that is great, but the motor is a bit slow with the D90. Basically, it is pushing a lot of glass for it to work at the optimal level. I did pick it up used for about $1000 from my local shop and did use it with the D90. There is also a 55-200mm & a 70-300 that aren't as expensive and can be found used for Rumors are that there will be a 18-300mm out soon.