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V-LOG Artifacting issues in dark areas

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10 minutes ago, Simon Young said:

V-log-L on GH5 and Gh5s is known to exhibit severe noise in shadows even at base iso. Even when properly exposed and with the highest bitrate. It’s one of the main reasons I’m holding my breath for the S1.

ya, I know right, that's why I'm seeing a lot of noise in dark areas, I thought it was an issue from my body, but when changing to cine-d, I don't see it anymore.

 

it's also because of my very cheap lens lol

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EOSHD Pro Color for Sony cameras EOSHD Pro LOG for Sony CamerasEOSHD C-LOG and Film Profiles for All Canon DSLRs

I think the most distracting element in the sample footage is the purple fringing and pulsing focus.

Log color profiles have very lifted shadows, so you will see a lot of noise in them when looking at it without a view LUT or grade.  Normally, you would apply a LUT, or an S-curve to push your shadows to near black and roll off the highlights.  Once the shadow area is compressed, you wont see as much noise, if any.  If you are going for a flat look, you will probably want to run some kind of denoise on the shadows to clean them up.

The advantage of LOG is that you have the option to compress shadows and highlights and have more flexibility in how much you want to lift them.  If you shoot with a standard profile its much harder to adjust shadow detail... if there is any at all.

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"Chromatic aberration, also known as “color fringing” or “purple fringing”, is a common optical problem that occurs when a lens is either unable to bring all wavelengths of color to the same focal plane, and/or when wavelengths of color are focused at different positions in the focal plane"

Its common on lenses when the aperture is open all the way. 

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If you ever end up with some of that in a shot you want to use, you can suppress it pretty well by using a soft mask around the problem area, key the purple and desaturate it.  Best to just avoid it if possible 😉or use a better lens if you have one when shooting high contrast.  

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4 minutes ago, thebrothersthre3 said:

"Chromatic aberration, also known as “color fringing” or “purple fringing”, is a common optical problem that occurs when a lens is either unable to bring all wavelengths of color to the same focal plane, and/or when wavelengths of color are focused at different positions in the focal plane"

Its common on lenses when the aperture is open all the way. 

yep, I have opened the lens 1.7 so that's why it has a very magenta look @thebrothersthre3

what do you think about the video? does the quality look good for you? I mean as all the others GH5? no particular issues with sensor?

2 minutes ago, Towd said:

If you ever end up with some of that in a shot you want to use, you can suppress it pretty well by using a soft mask around the problem area, key the purple and desaturate it.  Best to just avoid it if possible 😉or use a better lens if you have one when shooting high contrast.  

yes, I use cine lenses 17mm 0.95, samyang 16mm T2.0 etc. , I don't have this kind of thing with them

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5 minutes ago, @yan_berthemy_photography said:

what do you think about the video? does the quality look good for you?

Looks pretty normal for Log footage to me.  🤷‍♂️

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I watched a video a few times on my laptop, but the noise didn't look unusual.  I think you're just seeing a the noise in the lifted shadows.  Log is not a normal viewing format.  That is why view luts are typically created for monitoring on a set or in camera.  It is supposed to be adjusted to your delivery format (rec709, rec2020, DC3, film print) before final viewing. 

It's sometimes described as a "digital negative" in that like a film negative it holds a wider dynamic range than a final film print.  But when you view it without a display LUT, you are seeing all the gorey details that shouldn't be present or at least very suppressed in your final grade.

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9 hours ago, Simon Young said:

V-log-L on GH5 and Gh5s is known to exhibit severe noise in shadows even at base iso. Even when properly exposed and with the highest bitrate. It’s one of the main reasons I’m holding my breath for the S1.

Huh?  All cameras have noise in the shadows if they are underexposed and lifted in post. It's not a function of V-LOG or any picture profile but the limits of the sensor. The S1 'may' have more DR but you will still hit noise in the shadows at some point if they are beyond the DR of the sensor.

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23 minutes ago, Simon Young said:

Yes it’s an inherent problem with the body and v-log-l.

 

What exposure method are you using ? It would appear that exposing more and then bringing down the exposure in post to get the 'dark look' would be a possible solution. Noise in the shadows is simply tonal information beyond the usable DR of the camera and not an inherent camera issue. 

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25 minutes ago, Shirozina said:

What exposure method are you using ? It would appear that exposing more and then bringing down the exposure in post to get the 'dark look' would be a possible solution. Noise in the shadows is simply tonal information beyond the usable DR of the camera and not an inherent camera issue. 

I know how to correctly expose v-log-l (and s-log), but thanks for the condescension. As many already know the GH5s has a problem with its sensor/software and this has been debated in numerous articles and videos for a long time. Google is your friend.

It then comes down to the user’s and the clients tolerance for this kind of image issue. Chacun son goût. 

 

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5 hours ago, Simon Young said:

I know how to correctly expose v-log-l (and s-log), but thanks for the condescension. As many already know the GH5s has a problem with its sensor/software and this has been debated in numerous articles and videos for a long time. Google is your friend.

 

He wasn't being condescending, you were being sensitive. He was merely suggesting something to try that he thought may be helpful. 

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6 hours ago, Simon Young said:

I know how to correctly expose v-log-l (and s-log), but thanks for the condescension. As many already know the GH5s has a problem with its sensor/software and this has been debated in numerous articles and videos for a long time. Google is your friend.

It then comes down to the user’s and the clients tolerance for this kind of image issue. Chacun son goût. 

 

If you know how to expose V-LOG and S-LOG 'correctly' how did you set it on your test video?. What IRE value on your scopes is the horizontal light in the test scenes?

 

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Shooting at certain ISO's has been found to be a bad idea as shown in the video above. Example being 1600 iso is cleaner than 800. I think it has something to do with the native ISO's. 1600 is cleaner than 800, 3200 is cleaner than 2500 etc..

The banding issues in VFR seem really common too. It seems 60p is really the only good slo motion option. It does 4k 60p so that is not too shabby of an option though. 

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Just wanted to point out that the OP is shooting on a GH5 and not a GH5s.  They have totally different sensors and very different noise patterns.

I personally really like the GH5 noise.  At 1600 ISO and less it has very little color noise.  I actually really like the way it looks at 400 and 800 ISO... feels organic.

Also, the video posted above is a perfect example of why I believe you should analyze footage using a view LUT.  V-LOG maps black to 128 out of 0-1023 which I believe is higher than any other manufacturer.  You can take any camera and lift it's blacks 10% and see all kinds of garbage.  That said, the fixed pattern and color noise of the GH5s is not ideal.

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