Is there any way to shoot with a GH1 in low/no light and NOT GET MUD.

DanielRutter

DanielRutter

Active member
Hey guys;

I've tested every patch out there I can find... all I want to know is, can I use this camera at all in low light/no light situations and not get grey mud clouding my images?

I'd like to shoot some single source light scenes in the future for some of the films I've planned, but I may have to ditch the GH1 for this and use my trusty HV30. I cannot get clean blacks without mud otherwise.

Can anyone possibly tell me how I can modify a patch to get nice inky blacks (and no blown highlights) with this camera?

What I have:
GH17
Sandisk Extreme HD Video (30mb/s)
14-42mm lens (kit)
Pentax 50mm 1.7 (and I can't get inky blacks with this one either).

Help?
 
No, I was never able to get the GH1 to give me details in shadow areas in 1080p - it always went to mud. 720p was acceptable though.
 
Is this at all what you had in mind: http://www.fourseasonshd.com/cgi-bin/csvsearch.pl?db=db1&tp=tp17&search=lighttest1

It is difficult but not entirely hopeless to get somewhat decent low light shots with GH1. For starters I would experiment with GOP1 settings, Ryan Kozicki has posted his settings at http://vimeo.com/25218308

AFAIS, The only remaining obstacle for good low light shots is the vertical noise stripes that GH1 produces. There may not be a cure other than to start saving up for a GH2.
 
Yep, a GH2 is on the list mate.

I'm still stuck with the GH1 for a few more months, so in the meantime I'll just scrape by. I have experimented with the hacks before, but my Sandisk Extreme (30mb/s) cannot seem to keep up with any of the higher quality hacks.
 
Not neccessarily with a 1 light setup. But if you put much more light ONLY on your subject than you´d normally do and then crank down exposure until the highlights aren´t blown out anymore, you´d at the same time tell the gh1 to crush the lows to black.
 
I had a look at the RGB channels independently that the GH1 produces. It looks as if the worst offender is the blue channel. Red channel has some more noise than desired but the green channel is okay for the most part. Using expert color correction that separates the RGB channels and deals with them independently could improve the result. For example, adding some blur to the most coarse blue channel had a positive effect IMO.

I am going to look into this, because from previous experience I know the GH2 is not a complete solution to low light scenes either. 8 bits simply is not enough to represent a wide tonal range and most hues seem to be cut from the dark end leaving one with banding and posterization.
 
I separated RGB channels and graded them independently and finally added film grain to all three channels and combined. It helps fighting mud in low light scenes. If anybody is interested, here is a frame grab: http://www.fourseasonshd.com/blogLowLightTest11.jpg

The effect is a bit pronounced, it takes quite a bit of flattening and adding grain to mask the ugly noise patterns a.k.a mud that GH1 produces. Similar tactics should work well for GH2 where the effect does not need to be that strong.
 
Aki_Hartikainen said:
I separated RGB channels and graded them independently and finally added film grain to all three channels and combined. It helps fighting mud in low light scenes. If anybody is interested, here is a frame grab: http://www.fourseasonshd.com/blogLowLightTest11.jpg

The effect is a bit pronounced, it takes quite a bit of flattening and adding grain to mask the ugly noise patterns a.k.a mud that GH1 produces. Similar tactics should work well for GH2 where the effect does not need to be that strong.
Click to expand...

Would you explain step-by-step the process you did, please?
 
I can give the outline of the methods as this is still work in progress

1 Place three copies of a clip on timeline on video tracks 1, 2, 3 on top of each other.
2 Add Channel > Arithmetic filter for each clip.
3 Use Multiply as the Operator for the effect.
3 Drag down Red Value, Blue Value and Green value and leave one channel for each clip so that you now have red, blue and green copies of the clip on top of each other.
4 Add Levels to each copy of the clip and try to reduce contrast so that the mud patterns aren't visible (it's going to look washed out at this point).
5 Add Grain effect for each clip and use a preset film grain (reduce the intensity as the effect is multiplied by three).
6 Make another sequence or composition and grade the material to your liking using curves, for example.

This is how the filmlook plugins and color correctors treat the material and channels separately. For GH1 material there is no total freedom as the last grading will eventually start to bring out the original mud patterns. Also, the Add Grain filter is really slow to render and now you use three copies of it. I have the Add Grain filter copied from After Effects to Premiere Pro plugins folder as I find it faster to experiment with this in Adobe Premiere Pro.

Ideally there was a plugin or presets for GH1 and GH2 to make all this a bit more practical but if you want to control every aspect of the grading, there you have it.
 
There is clearly a bug somewhere in the transcoding pipeline that adds horrible noise to either R and B channels or the encoded U and V components. Most likely the encoded U and V. This could be as simple as a bad capacitor, for example, that leaks RF into the color signal. I am pretty sure Panasonic could have fixed this and release a GH1 Mark II with cleaner video. But that's not what Japan companies do, unfortunately.

So far it seems GH1 has decent Green channel and Red and Blue (or U and V) are rubbish. Majority of the mud resides in the R and B (or U and V before transcoding back to RGB). Because the Green is good, somewhere inside the camera a good Y signal component must exist, as well as clean R and B channels as the Y component is the sum of R+G+B.

Has anybody tried the HDMI output of GH1 to see how that looks? Is the HDMI operable while shooting video or only for playback of recorded material? Here is something that can be tested, as the mud resides in the color components, one could try to boost color saturation when shooting and then lowering color saturation in the post. If the mud value is constant, it would go down when lowering saturation. Playing with white balance or actual color filters in front of the lens might help also. The idea is to try to shift the hues to the one channel that does not have mud when shooting so that in post balancing the hues could minimize the use of the mud components of the camera.
 
I put the White Balance in GH1 to 10000K which made the image reddish. Then in Adobe Premiere Pro used Fast Color Corrector. As one would guess, the mud eased the more to the green and thus natural the colors turned. As soon as I have some time, I am going to test more camera and color correction settings.
 
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