i see no grain in well lit scenes in iso 160. 400 is a different story of course. maybe post some screenshots with grain in iso 160? :)

I have exactly the same issue, it gets slightly better if you dial back the sharpening and contrast, but it is always there. I have come to terms with this as follows--for certain scenes (flowing motion), I very slightly prefer the GH1--especially now that 24p is pretty stable--but I realize that most people are not going to notice the difference, or, even stranger from an artistic point of view, if you leave the settings at "0000" many people will like the saturated color and pseudo sharpness. And I have to say, sitting far from the screen, it does look good. It looks real good. But I'm keeping the GH1 for two reasons. Reason one is for sure the grain, reason two is, if someone offered me a camera like that for $375, I would buy it no hesitation.
The hack for the GH2 is getting better and better, but I think the grain is just a function of the denser sensor. Hey, quite a few ppl really like the GH2 grain. And in certain situations, it does look filmic. While I was testing the Rigs hack today (thanks again), I just shot a few trees in the backyard at ISO 100, popped it into the media player, and like, wow. But hey, realistically, it is a very small difference and the GH2 is a great cam. We notice it because we live with all the time.
Grain wise, I have been disappointed with ETC. I expected cleaner video. But it is a very handy feature. Cant wait to see the firmware update--maybe they will dial back the in cam processing a tad more and that will split the difference in the grain.
I also think that we haven't squeezed the max out of the GH1.
Down the line, either the Canon 5D Mk3 or something similar will lay the grain to rest--you will only add it if you want it. For now, I'm enjoying both cams.
For sure double check everything in the signal path for and DSP in the chain that might give a bit more grain, but I'm sure you thought of that.

One more thing--have you tried shooting daylight white balance then adjusting the WB in post for your lights? Could be you are getting a lot of blue channel noise, or other WB noise. A long shot, but sometimes part of the noise is WB related.

@Ralph_B

Hey RB

I have NeatV, could you please give me a quick overview of your settings or do you go auto? No rush just when you get a chance.

Thanks

Neat Video Guide

The key thing in Neat Video is to get a clean noise sample. If you do this, everything else will fall into place. Ideally you should shoot a gray card when filming. Or you could throw the picture wildly out of focus to get a smooth area of noise. As you know, Neat Video tries to auto-detect a clean area of noise. I would say 80% of the time it does a good job, but sometimes you need to manually move the square around to find a better area. Press the Auto-Profile button again to register the new area. If the lighting and exposure doesn't change, you can use the same noise sample for multiple shots. (Neat Video remembers the last used noise sample)

Here are my recomendations for the Noise Filter Settings:

Noise Levels:
Leave both Luminance and Chrominace at 0. This is the optimum setting if you have a clean noise sample. The only time you would change these would be to compensate for a less than perfect noise sample. But it never works as good as getting a clean noise sample in the first place.

Noise Reduction Amounts:
Neat Video defaults the Luminance channel to 60%. This is good for a still image, but not for video. There will be too much pulsing between frames. Drop it to 30%. If you have Preview turned on, it may look like it's doing nothing at all, but don't worry, it is.
Chrominance channels is fine at it's default of 100%.

I've found no use for "Smooth edges" and I recommend keeping "Sharpening Amount" at 0.
"Very low freq" may be useful if the picture has large blotchy areas of noise. With the GH2, I use it with clips shot with ETC at high ISOs. For most noise jobs though, I leave it off.

Now we come to an important part that most people don't understand, and that's the "Temporal filter." After you hit Apply, you may think you're done, but you're not. In the final dialog box, you see the Temporal filter. What this does is selectively blend areas from frames on both sides of the current frame. This is absolutely essential for video to eliminate pulsing. I find that a Radius of 2 frames to be excellent for all but the worst cases. Threshold is fine at 0. The Temporal filter does slow down rendering time, so don't use any more than you need.

The results of Neat Video can be absolutely astounding and worth the long render time.

NOTE: Feel free to copy this guide anywhere you want.

@Ralph_B

Thanks for Neat Video tips :-)

Nice Neat Video tips--I would add that if I am going to add sharpening, I do sometimes use the Neat Video sharpening. I'm assuming it does not sharpen the noise

Tell me about it. Geez... using cheap LED lights as the only lighting sources in a dark room wasn't easy task. I looked like Greench. I saw beautiful sunlight today and felt like redemption from Shawshank.

It's possible to shift color for photo in GH. Go to WB and press down. But that didn't work for video.

@Ralph_B
Thanks a lot

@Ralph_B I'm still not sure I get it.

If I use a WB that's deliberately got less red in it, aren't I just going to have to boost the red channel back in post, and only reintroduce all that noise again? Only now it's boosted post AVCHD compression, which will surely be worse?

Unless some of the WB's are boosting the red channel until it's clipping?

RE: Indoor white balance

Sorry for any confusion. I'm not saying you should use indoor white balance all the time. That would be absurd. What I'm saying is that when you use high ISO's, using indoor white balance is an effective way to reduce the noise. Now, when you use high ISO's, chances are it's in a low light interior or exterior at night. In both situations, indoor white balance will usually work without any significant color correction necessary.

I just don't want you to knee jerk at night and say, "oh, I'm outdoors. I must use daylight white balance". (Not to be confused with "jerk off at night". That's fine.)

@rigs
>I do notice more grain with the hack
Show me the grain. I find it hard to talk about what I cannot see. :-)

Make sure you're using the correct Ptools version... for a while I was using 3.62 patches with the v3.61 Ptools and was getting unexpected noise. I realized my mistake when I was re-organizing my computer... ;)