I have to disagree for the Z1. I have seen from a doc I am doing at HDV for a prefecture here, some samples that I could take only by PD170 with which I am shooting the show at TV.
But of course this is my understanding. Even if we pushed the gain we saw no bad grain. Z1 isn't in par with a PD170 in low light but is better than my HV30 which claims that it is at 3 lux.
While at bright light HV30 is directly comparable with the Z1 at low light Z1 is better. So let me say that Z1 for an HDV camera is very good in low light and a lot better than V1.