Hello and welcome to Cameralabs.
If you have a look at the crops on the noise results page for the FZ30 at...
http://www.cameralabs.com/reviews/Panas ... ge4c.shtml
...you can see its noise levels are noticeably higher than its rivals, even at 200 ISO.
This could be due to a number of factors, although we suspect its mostly down to the sensor. I would consequently try and only use the FZ30 at an ISO of 100 where possible. At least the optical stabilisation will help you handhold at slower shutter speeds.
It will be interesting to see how the new FZ50 compares, especally as it has both higher resolution and higher sensitivities on offer.