Ben_B
Veteran
I believe I have found a stop-gap measure to prevent or at least drastically reduce CMOS banding on the GH1 in a variety of different circumstances. I realized that banding could potentially be caused by our relentless pursuit of the flattest and most-aliasing free possible in-camera picture profile. This has caused many people to shoot on settings like "smooth" and "nostalgic" with contrast and sharpness turned down, etc. By forcing the camera to light up darker areas with a flat picture profile, we're actually introducing banding. While it's possible some of this can be negated in post by adding contrast, it's a good idea to try and get a clean image on set, and I figured some people would be interested in this.
Hypothesis:
1) Using a more contrasty in camera profile (dynamic) with contrast turned up, will cause normally under exposed areas to underexpose further, but will reduce banding because the camera is not bringing those areas up in the picture profile.
2) Increasing sharpness will reduce banding because areas with more detail and critical focus are less likely to exhibit banding, and you're less likely to notice banding that is there, thanks to the texture and increased attention payed to these areas by the compression algorithm.
3) Decreasing saturation will reduce banding because noise is often introduced as saturation is increased.
4) Increasing noise reduction will reduce banding because that's what it's designed to do, among other things.
Results for Comparison:
1) My preferred settings for everyday shooting: Standard, Contrast -2, Sharpness +1, Saturation +/- 0, NR -2.
2) Very Flat GH1 settings, Nostalgic, Contrast -2, Sharpness -2, Saturation -2, NR -2. The "do it in post approach."
3) Ultra Contrast GH1 settings, hypothesized by me to reduce banding: Dynamic, Contrast +2, Sharpness +2, Saturation -2, NR +2.
All shots shot ISO 1600, f/1.7 (lumix g 20mm f/1.7 asph.), 1/30th of a second, FHD 1080/24p, no-native, C settings GH1 hack. They're all also shot sRGB because I didn't think to set my camera to Adobe RGB…which I know people do to get Very Flat, my bad. All files were converted to ProRes 422 and exported from Final Cut Pro as single frames. No gamma correction was applied during transcoding.
Click links for full resolution images.
First shot: lit by a 50/60 watt equiv CFL about 15 feet away in a downward deflecting hanging lamp in a large kitchen. Not much light to speak of, nothing like the same light in a small room.
Settings 1:
http://farm5.static.flickr.com/4089/4976332128_85c1dee97b_o.png
Set
tings 2:
http://farm5.static.flickr.com/4087/4975720835_a94caa98b1_o.png
Settings 3:
http://farm5.static.flickr.com/4154/4975719747_b6cbc7f00b_o.png
Second shot:
Just that computer screen, totally dark room.
Settings 1:
http://farm5.static.flickr.com/4128/4975720155_b438cbb672_o.png
Settings 2:
http://farm5.static.flickr.com/4149/4976334214_af24b55438_o.png
Settings 3:
http://farm5.static.flickr.com/4104/4975721059_a9c5339469_o.png
Third shot:
50/60 watt equiv CFL (perhaps two, inside a frosted glass ceiling fixture) lightbulb on in next room behind camera, mostly obscured by doorway…very little light.
Settings 1:
http://farm5.static.flickr.com/4109/4976334560_2b96510ae0_o.png
Settings 2:
http://farm5.static.flickr.com/4103/4975722153_81f77c9441_o.png
Settings 3:
http://farm5.static.flickr.com/4127/4975721865_5191d0c5b8_o.png
Conclusion:
Option 3, in camera high contrast seemed to fair the best, followed by option 1, my personal typical settings, and last by option 2, Very Flat with no modifications. In Shot 2, settings 1 appeared worse due to heavy grain caused by the blueness and the saturation, but I think the banding was still not as bad.
Shot 1 was probably the best example of the kind of shot you might expect to actually want to shoot, the other two were extremes to demonstrate the point, and option 3 really resulted in an image that was too dark. However, you could easily bring light in to your subject but avoid background banding in these situations. If you look at shot 3 you'll see banding in the black area with Standard and Nostalgic but not with Dynamic.
While I realize that simply increasing contrast whether in camera or in post is not a viable option for everyone and every shoot, I do believe it is a decent solution, stop gap, band-aid, for those of us trying to shoot dark, dramatic scenes, where we've lit our actors but don't necessarily want a bright background, or are shooting out on a street at night under reasonable circumstances. For example, if you stick your subject under a street light or even a flashlight or something but don't want the wall of the nearby building to be covered in banding this could work wonders…however in very dark situations you may just not get to see much of anything. Furthermore, similar results may be possible by tweaking your footage in post, but so far I have had better luck with the in-camera profile to reduce banding…perhaps someone will repost one of these stills with some post work? I've noticed it still keeps the banding in the better exposed areas which isn't there in the High Contrast in camera option. I will be posting more results as I create them, and invite you to do the same. Thanks.
OVERALL CONCLUSION:
Your super flat settings are hurting you in low light when it comes to banding without extensively bring up contrast in post anyway. Might as well see how much you can reduce banding on set so you know what you're getting...you might not be able to fix it in post. With very contrasty settings you reduce banding and immediately know where you should be increasing light to make up for the loss, rather than having to guess at it and hope you're right when you get to post.
Hypothesis:
1) Using a more contrasty in camera profile (dynamic) with contrast turned up, will cause normally under exposed areas to underexpose further, but will reduce banding because the camera is not bringing those areas up in the picture profile.
2) Increasing sharpness will reduce banding because areas with more detail and critical focus are less likely to exhibit banding, and you're less likely to notice banding that is there, thanks to the texture and increased attention payed to these areas by the compression algorithm.
3) Decreasing saturation will reduce banding because noise is often introduced as saturation is increased.
4) Increasing noise reduction will reduce banding because that's what it's designed to do, among other things.
Results for Comparison:
1) My preferred settings for everyday shooting: Standard, Contrast -2, Sharpness +1, Saturation +/- 0, NR -2.
2) Very Flat GH1 settings, Nostalgic, Contrast -2, Sharpness -2, Saturation -2, NR -2. The "do it in post approach."
3) Ultra Contrast GH1 settings, hypothesized by me to reduce banding: Dynamic, Contrast +2, Sharpness +2, Saturation -2, NR +2.
All shots shot ISO 1600, f/1.7 (lumix g 20mm f/1.7 asph.), 1/30th of a second, FHD 1080/24p, no-native, C settings GH1 hack. They're all also shot sRGB because I didn't think to set my camera to Adobe RGB…which I know people do to get Very Flat, my bad. All files were converted to ProRes 422 and exported from Final Cut Pro as single frames. No gamma correction was applied during transcoding.
Click links for full resolution images.
First shot: lit by a 50/60 watt equiv CFL about 15 feet away in a downward deflecting hanging lamp in a large kitchen. Not much light to speak of, nothing like the same light in a small room.
Settings 1:
http://farm5.static.flickr.com/4089/4976332128_85c1dee97b_o.png
Set
tings 2:
http://farm5.static.flickr.com/4087/4975720835_a94caa98b1_o.png
Settings 3:
http://farm5.static.flickr.com/4154/4975719747_b6cbc7f00b_o.png
Second shot:
Just that computer screen, totally dark room.
Settings 1:
http://farm5.static.flickr.com/4128/4975720155_b438cbb672_o.png
Settings 2:
http://farm5.static.flickr.com/4149/4976334214_af24b55438_o.png
Settings 3:
http://farm5.static.flickr.com/4104/4975721059_a9c5339469_o.png
Third shot:
50/60 watt equiv CFL (perhaps two, inside a frosted glass ceiling fixture) lightbulb on in next room behind camera, mostly obscured by doorway…very little light.
Settings 1:
http://farm5.static.flickr.com/4109/4976334560_2b96510ae0_o.png
Settings 2:
http://farm5.static.flickr.com/4103/4975722153_81f77c9441_o.png
Settings 3:
http://farm5.static.flickr.com/4127/4975721865_5191d0c5b8_o.png
Conclusion:
Option 3, in camera high contrast seemed to fair the best, followed by option 1, my personal typical settings, and last by option 2, Very Flat with no modifications. In Shot 2, settings 1 appeared worse due to heavy grain caused by the blueness and the saturation, but I think the banding was still not as bad.
Shot 1 was probably the best example of the kind of shot you might expect to actually want to shoot, the other two were extremes to demonstrate the point, and option 3 really resulted in an image that was too dark. However, you could easily bring light in to your subject but avoid background banding in these situations. If you look at shot 3 you'll see banding in the black area with Standard and Nostalgic but not with Dynamic.
While I realize that simply increasing contrast whether in camera or in post is not a viable option for everyone and every shoot, I do believe it is a decent solution, stop gap, band-aid, for those of us trying to shoot dark, dramatic scenes, where we've lit our actors but don't necessarily want a bright background, or are shooting out on a street at night under reasonable circumstances. For example, if you stick your subject under a street light or even a flashlight or something but don't want the wall of the nearby building to be covered in banding this could work wonders…however in very dark situations you may just not get to see much of anything. Furthermore, similar results may be possible by tweaking your footage in post, but so far I have had better luck with the in-camera profile to reduce banding…perhaps someone will repost one of these stills with some post work? I've noticed it still keeps the banding in the better exposed areas which isn't there in the High Contrast in camera option. I will be posting more results as I create them, and invite you to do the same. Thanks.
OVERALL CONCLUSION:
Your super flat settings are hurting you in low light when it comes to banding without extensively bring up contrast in post anyway. Might as well see how much you can reduce banding on set so you know what you're getting...you might not be able to fix it in post. With very contrasty settings you reduce banding and immediately know where you should be increasing light to make up for the loss, rather than having to guess at it and hope you're right when you get to post.
Last edited:
I know....