Originally Posted by harrison425
Yes, 3rd party brands should work just fine on them with AF. Make sure you're buying the lens that for Nikon and have AF ON the lens body too.
That's not entirely true. The D3000 lacks an in-body AF motor so any lenses that don't have built-in motors won't be able to AF on the camera. It's only an issue with the entry level Nikon bodies though. The D90/D7000 and above bodies don't have this issue since they've built in AF motors.