100-400 is good. depending on your shutter and fstop
not too sure how much noise will be introduced when iso goes up with the d5000. i know the d3 and d300 can shoot up to 1000 with barely any noise.
I usually shoot on manual to overexpose a little. And overexposing is risky since you cant make the hot spots detailed again. Underexposing it will allow you to make it brighter in photoshop and keep the details.
not too sure how much noise will be introduced when iso goes up with the d5000. i know the d3 and d300 can shoot up to 1000 with barely any noise.
I usually shoot on manual to overexpose a little. And overexposing is risky since you cant make the hot spots detailed again. Underexposing it will allow you to make it brighter in photoshop and keep the details.