Tagged with noise - Personal View Talks

How to improve low light image quality from iso 12800 and 6400

apefos — Wed, 11 Jan 2012 13:49:22 +0000

Learn how to match C300 and FS100 low light image quality with the GH2 (on vimeo), you can download the neatvideo profiles and presets in this thread post number 10, these saved profiles and presets are updated with a new fine tweaking to get a much better results, also if you want more information go to vimeo and read the video description.

Noise Test: Panasonic GH2 with Driftwood's 176mb GOP1

Gabel — Thu, 06 Oct 2011 13:10:38 +0000

With the hack we all know how noise has become more apparent (because of the sharpness). I figured that it was time to test out and see the levels at different ISO values. So here are my results (since I'm not a Vimeo-pro member, there is some bad compression, but have the originals available for upload).

I shot 10 seconds (which now might have been too long) at each ISO value, with the body cap on. Settings were:
- Driftwood's "GOPStoppa" GOP1 176mb hack.
- White balance at 5600K
- Shutter at 50

I've upped the mids in After Effects quite a bit.

The major surprise was 320, which looks awful... Shot a second one, but had the same results! Very surprising...

Here's the video:

And the link to the original clips:
http://www.megaupload.com/?d=5M4N08F1

GH2 ETC-mode noise penalty

balazer — Thu, 03 Nov 2011 21:06:56 +0000

I have a 50-mm lens, which gives almost the same field of view as the Lumix 20-mm lens with ETC turned on, so I did a little experiment to see how much noise ETC adds. This was just eyeballing it, i.e., not scientifically rigorous. Tests were performed with 100-Mbps intra recording and NR at -2.

The ETC noise penalty is: 2 and 2/3 stops. Specifically, the picture with ETC off at 3200 ISO looks about as noisy as the picture with ETC on at 500 ISO.

What I find interesting about this result is that increasing the sensitivity by a factor of 6.4 increases noise about as much as using 6.76 times as much sensor area (2.6^2) reduces noise. In other words, the GH2 is making very good use of those 16 million pixels when it downsamples to 1080p, giving nearly all the reduction in noise that you would hope to have from using a larger sensor area and correspondingly larger lens aperture.

Though there definitely is aliasing in the downsampled picture. The aliasing is not as bad as in the GH1's 1080p, or in the Canon 5dmkii, but it's there, and it makes you see things that you shouldn't be seeing. I can put together a little demonstration video if anyone is interested, but that's a separate topic.

Digital Noise in Blue Sky - Vanilla Hack

mattodowd — Tue, 23 Oct 2012 02:19:40 +0000

Hey all -

Wanted to throw this out to the community and see if there were any thoughts. Going through footage from this weekend's blue sky shoot, and on top of the expected mild posterization, I'm seeing some subtle but noticeable digital noise.

Any thoughts? Here are the specs:

GH2 running Vanilla Hack Firmware V1.1 ISO 160 Nostalgic -2, -2, 0, -1

It was very bright light, but properly exposed with an ND / Polarizing filter.

Thanks, Matt

Commercial / promo for Sagene, Oslo, Norway - flow motion hack

cekrem — Mon, 08 Oct 2012 11:55:27 +0000

http://vimeo.com/welterwerk/sagene

Welterwerk Filmkompani recently shot this short promo for Sagene, a district of Oslo, Norway. Shot exclusively on our hacked GH2. Zeiss glass! :) Time was short, and the budget was ridiculously low - but we’re quite happy with the result.

The rain-like, diagonal noise showed up in quite a few shots, but disappeared when transcoding in 5DtoRGB. Weird! Other than that, the GH2 - and the hack - performed like expected: top notch!

Enjoy! And if you haven’t already, check out Welterwerks own promo video: http://vimeo.com/welterwerk/welterwerk

Getting to the bottom of the noise

Bania — Mon, 17 Sep 2012 07:54:05 +0000

Hi Guys.

I've just started reviewing footage from a recent shoot and am a little perturbed by the amount of noise showing up in shadow details. The problem has occurred on a range of shots in different lighting conditions and even at very low ISOs.

I was using a GH2 for the shoot, with LPowell's Flowmotion 2.02 hack. This was the first time I had used a Gh2 (let alone a hacked one) so it was certainly a baptism of fire. For the majority of shooting I was using a lumix 7-14 ultra-wide lens.

I've uploaded a short clip with three different shots, each displaying the telltale noise. In the first, the noise is visible above the character's foot, on the side of the piano. This was shot at a ISO800 so it makes sense that there will be noise. Still, it seems like there is more than there should be. the second clip was shot at iso160 yet there is still a fair amount of noise showing up in the man's beanie. In the third clip, also shot at iso160, again there is a lot of noise in the man's sweatshirt.

http://www.mediafire.com/?1m7c10p98tvy883

I didn't fully test the patch and cam before the shoot so at the end of the day it's my problem, but I'm hoping someone can shed some light on the source of the issue so I can avoid this next time around.

Cheers

Noise on GH2 footage at ISO 160

GuilleKloetzer — Fri, 08 Jun 2012 20:11:17 +0000

I´ve shot an interview for a TV series, on tripod, day, overcast, plenty of light. Anything looked ok on the LCD while shooting BUT, when we downloaded the file and imported on Final Cut we found a dreadful noise was all over the ground and on some portions of the character being interviewed. Then we went to check the original file on VLC2 and the noise is not so bad there but quite hard to swallow anyway. Any clues of what happened? THANKS IN ADVANCE

Original MTS file can be downloaded on http://www.mediafire.com/?e772u2w69srha7f

HACK Driftwood´s spanmybitchup lens Panasonic, 14-45mm at 14mm, aprox f16 Settings were: ISO 160 WB interior shutter 1/200 HBR nostalgic video out pal

Yall like Puerto Rico?

NoiseSoulCinema — Fri, 24 Aug 2012 01:05:46 +0000

Took a vacation to Puerto Rico with my hacked GH2, and this is what I chose to film and hodge podge together.

GH2 at iso 12800

ShineHunter — Tue, 07 Aug 2012 14:51:02 +0000

I'm new to all this, but I'm a quick learner. I'm seeing large blue and smaller darker band when at iso 12800. Also the noise seems a lot more than normal for this camera. You guy's know your stuff, is this all normal or do I have a faulty GH2?

CLUSTER v6 'Nebular' Kit lens 14-42mm f3.5 1/50 iso12800 Smooth -2 on all.
I.Dynamic/I resolution off.

GH2 + RODE VideoMic, high-pitched noise with levels 2-4.

fetzu — Sun, 27 May 2012 14:06:08 +0000

While doing some test shoots with the GH2 + VideoMic the other week, I realized (when reviewing the files in the NLE) that the camera had pickup up a really annoying high-pitched (constant) noise. I blamed it on the connections, so I tried to reproduce the noise at home and the noise was still there. Then I blamed it on the 3.5 -> 2.5 adapter (which is a short cable), and decided to purchase another (a right angle adapter from hosa, the GMP-467) and the noise still persists.

When I set the audio input level to the lowest setting ("level 1" if I am not mistaken), the noise is inaudible.. but then again the camera is barely picking up any sound. And, quite logically, increasing the input level adds its share of noise. The noise is very noticeable at 2 and unbearable at 4.

I'm using driftwood's Sedna A (which has an audio hack included, as I understand). I tried using the VideoMic with another sound device (a zoom h1), and couldn't reproduce that high pitched noise..

Has anyone experienced anything similar? Is this supposed to be the camera's default behavior? Am I missing something?

Micromuff Skinny - Deadcat for the GH2

tvpglabs — Thu, 24 May 2012 10:01:37 +0000

Micromuff has come up with a product specifically designed for the GH2: The Skinny. I reviewed it on my blog: http://tvpglabs.com/?p=469 and made the following video review:

My takeaway: it's not perfect, but it's good enough to insure a sync track on a multiple camera shoot. What do you guys think?

Motion compensated temporal noise reduction

balazer — Mon, 30 Apr 2012 04:17:56 +0000

Vimeo's compression can't handle all of that noise, so please download a high bit rate version and 1080p samples at http://minus.com/mGH2_low_light_tests/1g

split screen original/denoised

0 s: 720/60p 50 Mbps, ISO 12800, 1/60 s shutter. denoised, decimated

12 s: 1080/30p 135 Mbps, ISO 12800, 1/60 s shutter. denoised, downscaled

23 s: 1080/30p 135 Mbps, ISO 6400, 1/30 s shutter. downscaled, denoised

36 s: 1080/15p 22 Mbps, ISO 3200, 1/15 s shutter. downscaled, denoised, interframe 2x

43 s: 1080/10p 11 Mbps, ISO 2000, 1/10 s shutter. downscaled, denoised, interframe 3x

53 s: 1080/10p 15 Mbps, ISO 12800, 1/10 s shutter. downscaled, denoised, interframe 3x

then repeats, full frame denoised

Part of these samples is simply a test of the trade-offs of high ISOs and long exposure times, with motion compensated frame rate conversion to boost the frame rate of the slow shutter speed samples.

For the noise reduction, I took the TemporalDegrain Avisynth script and rewrote portions of it to better deal with GH2 high ISO footage. Much of the effort was in getting the motion search to produce more accurate vectors in the presence of high noise. I was able to improve the motion search a lot, but it's not perfect. It often misses motion in large low-contrast areas of the image. The other work was to limit the differences between the de-noised output and the source, so as to reduce or hide ghosting artifacts from when the motion search was incorrect. This has a side effect of bringing back some of the noise. I was actually quite conservative about this, trying to keep the footage looking natural, and striking a balance that minimizes all of the different kinds of noise and artifacts. The noise reduction is purely temporal - i.e., accomplished by averaging pixel values across frames. Adding some kind of spatial noise reduction would probably help.

The script is extremely slow on full 1080p frames. To use it on 1080p, you'll need to find some way to divide up the frame and process the pieces in separate instances of Avisynth. 720p processing is not too slow.

There are lots of options in the script that I'll be happy to explain. There are only three or four options that you might want to change. The defaults (which I used for all of the samples) are optimized for 1080p at ISO 12800.

I compared my noise reduction output to that of RE:Vision Effects' DE:Noise plugin, and I think the script does a better job, though the plugin is much much faster.

Please post experiences and usage info for other motion compensated noise reduction software.

Sensors: Dynamic range

Vitaliy_Kiselev — Wed, 18 Apr 2012 12:57:07 +0000

Via: http://www.manufacturingnewsletter.com/docs/automate2011-advanced-camera-image-sensor-technology.pdf

25mm F/0.95 Voigtlander - Shooting in the dark

Alexauwa — Mon, 19 Mar 2012 15:08:24 +0000

Hi everyone,

I am shooting on the Voigtlander 25 mm f0.95. I've tried several shots, insight and outsight. I've noticed that in some parts the dark areas were absolutely clear, no noise at all, but in some where were. I've keep ISO between 320 - 640, f0.95.

How do I get, even if there is less light, the most best possible result - here a clean picture? Do I have to raise ISO in order ta achieve better results? (Sensor need more light sensitvity to bring out details, can you shoot on too low ISO?) I always thought: lower IS0 value= better picture quality.

How do you handle night shoots, any tricks? Any help would be much appreciated!

Thanks, Alex

GH2 noise reduction tips

haribabis — Mon, 13 Feb 2012 05:28:41 +0000

I move my thread here, as suggested, to start a new topic.

latest trick-tip. I try it and it works, even with unhacked 1.1 firmware!!! You have just to start with whitebalancing a little to blue to reduce the red channel. Of course the 320/640 etc bug exist.

Noise when shooting VIDEO of landscape with aperture of 22

Jrb — Fri, 27 Jan 2012 08:11:57 +0000

Very bright sunny day standing on a hill looking across to other large hills far away.

14-140mm kits lens, 50 shutter speed, ISO 160, aperture closed down for correct exposure to 22 (no ND used).

Once I got back and checked footage on large screen I noticed this video had quite a lot of noise.

The shot that I took with the Voiglander 25mm f0.95 didn't seem to have much noise. I think this was set at f2.8 and then I used a lightcraft variable ND to get the correct exposure.

So my question is... Does closing down the aperture fully (22) create this horrid noise?

Does anyone have any advise on what would be a good aperture to use when shooting landscapes? Is there a recommended aperture not to go passed, like 16 or something?

Panasonic GH2 - possible to stop all in-camera Noise Reduction?

Lyris — Sun, 29 Jan 2012 17:03:20 +0000

Hello all, Many thanks for your amazing work in unlocking the Panasonic GH2's full potential.

Viewing the hacked footage, the only complaint I have left is that the camera appears to perform some sort of spatial filtering (presumably for NR purposes) in dark areas. The noise in the midtones and brighter areas is fine and high-frequency, and almost film-grain like. However, shadow noise appears to be spatially filtered, with fine details missing. This occurs even with all the NR settings disabled on the camera, and is problematic for doing further NR in post production, especially when underexposed footage needs to be brightened.

Is this something you're aware of? Can it be disabled to give us a "warts and all" image from the camera?

Example (gamma raised to show issue): http://img269.imageshack.us/img269/1715/gh2noise.jpg

Proposition about variable ETC mode

stuckvoxel — Wed, 14 Dec 2011 00:55:56 +0000

I'm here to make the case again to Vitaliy to figure out how to control the GH2's cropping and downscaling features, and allow us to change them through ptool. (If it's not obvious, this post concerns video, not stills.)

There's a universe of old C-mount lenses out there, in 1/3, 1/2, 2/3, 1 inch, and 16mm, each of which makes a different sized image circle. To use each of these lenses to their fullest, you want your camera's sensor to be slightly smaller than that image circle. With the GH2 we have a camera with the capability to have any sensor size you want, up to 4/3. The "universal-format camera" is in our hands, we just need some awesome hardware hacker to unlock it!

The "proof" that the GH2 is capable of this is found in the facts that 1) the GH2 is currently able (has the processing power) to take the entire 4/3-inch, 4976x2800, 16:9 portion of the sensor, and downscale that to 1920x1080 or 1280x720 (did I see that some of you had got the GH2 to use other sizes?); and 2) the GH2 is also capable of using only part of the frame, with no downsampling (as demonstrated in ETC mode). So it's not much of a stretch to believe that the GH2 is capable of taking any 16:9 subset of the sensor's pixels AND downscaling that to any 16:9 pixel size! (Indeed, by de-centering the crop region, you could correct for the inevitable misalignment between lens and sensor.)

So the challenge to you, Vitaliy, is to figure out how to choose that subset of pixels and add that item to ptool. Then, for example, I can take the 4160x2340 subset of the GH2 sensor's 4976x2800 pixels* that my cheap, fast, good 1-inch format C-mount lens can cover, and get great video. Right now, the only way to use this lens is to crop the video in post, which kills resolution (up-sampling, yecch) and wastes bandwidth encoding parts of the frame that are going to be cropped away.

(*yes I know it's more complicated than that, since it's a Bayer sensor, and the full sensor is more like 4976x3456, but you know what I mean.)

Further, as balazer pointed out in the posting "GH2 ETC-mode noise penalty" ( www.personal-view.com/talks/discussion/comment/27293 ) the GH2's downsampling achieves 95% of theoretical efficiency at noise reduction by binning. So in my example above, where I'd be using about 70% of the area of the whole 16:9 portion of the sensor, my lens would have only a half-stop noise penalty compared to some way overpriced lens that could light the whole 4/3 frame--if such a lens even exists in this focal length. And spatial resolution (as in lines per picture height) would still be excellent, since the downscaling to 1920x1080 would still be a reduction to around 45% of the raw image. So the result would look far better than the existing ETC mode.

Suddenly, all that old C-mount glass, as ridiculously overpriced as some of it has become, will finally be worth using. No more dark corners. No more frustration with not knowing what image format a given C-mount lens that you find on eBay was designed for. If it's a C-mount lens, your GH2 would be able to use it to full advantage. As a side effect, this would encourage more reasonable pricing of Noktons, Noktors, and the rare cine lens that happens to fully cover 4/3.

Here's hoping that with Panasonic's release of the v1.1 firmware, this level of control will finally be possible! Perhaps this feature can be implemented as a modification to ETC mode, which would provide a handy way of turning this feature on and off through the camera's menu in the field.

Thanks again, Vitaliy, for all you've done.

GH2 Neat Video noise profiles

Meierhans — Wed, 21 Sep 2011 17:32:38 +0000

Hi pixel peepers and codec tweakers,

sadly I don´t have the time nor skills to join the battle for best compression settings. So I simply took driftwoods 132 GOP 3 settings as given for the moment, recorded some flat surfaces and threw this into Neat Video. Then tweaked a little, checked with real footage. All 24H, Nostalgic -2, -2, -1, -2, shutter 50... any idea if this matters? I guess FPS will.. but does shutter as well?

However, here is my outcome, not scientific in any way, be warned. If you can do better.. let us know.

(Make sure to set temporal filter ratio at least to 2, so Mister Clean knows enough about the past and the future to make the right decisions...)