I've been converting some old Hi8 tapes to digital, and I've run into this problem many times. You have to take a two-step approach: first, use one of the light or brightness/contrast filters to get the video to the brightness you want, and then apply one of the noise reduction filters. You'll have to manually tweak the NR filter to get it looking ok, but eventually you'll find a sweet spot that draws a good balance between video noise and video artifacts.