I know a lot of setting you can do in bios and windows, which helps out with input lag. I never used 1000fps camera, because it is expensive and i can tell down to 6 ms difference in input lag.
But there is now 1000fps camera only for 120$. Problem is it is only 224x64 pixels, i don't even know if you can tell on this resolution anything.
And how do you even know for sure how much input lag is there, in fps games maybe animation is delayed a bit and i don't actually know if it register kill from that moment you pressed button and it shoot on your enemy, there can be network delay too. Or in rts you can see your command is executed when green symbol appears on map, i don't know if you would be able to tell on 222x64. Does someone use this for measuring input lag ?