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Zak Forsman

V-Log L captured in 8 bit vs 10 bit

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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

Good article. I've shot a few more things in the last day or two and realize that scenes with alot of light and minimal shadows really shine. Scenes with alot of dark shadows and bright lights work best when the shadows are brought down to near crushing. Alot of midtones with few shadows and highlights in a scene are the worst.

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Yeah, i think midtones are where the sacrifice in tonality hits the hardest. Incidentally, some of James Miller's V-Log LUTs have some kind of noise reducing voodoo. Not all, but I've come across a few that manage to suppress noise even in a low contrast look.

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there are over 200 in the GH4 V-Log pack. They're hard to remember but I know i used AA20 on ISO 1600 clips and was impressed. There are others but the naming convention makes them hard to remember.

He also has a reverse Cinelike to V-Log LUT so you can use the set with stuff you might already have shot.

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VLOG is going to be a tricky beast to tame.   I was shooting some stuff outside the house last night and some looks super clean, and some looks super noisy.  My emotions went between disappointment and joy a half dozen times in a half hour!   

People are going to be so frustrated with this until they wrap their  hands around exactly how it all works.    I need more time with it. 

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Here is V-Log L at 8 bit, captured internally.

ZxXNGVL.jpg

And here it is at 10 bit, captured externally.

ayUDZT4.jpg

These are 1:1 extractions from the 4k frame.

Wrote more on the subject here...
http://zakforsman.com/a-dynamic-range-and-tonality-comparison-of-v-log-l-on-the-gh4/

Thats pretty damning evidence. SO many nasty colour artefacts in the 8bit pic. Not to mention the banding ...

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Guest Ebrahim Saadawi

You seems quite knowledgable about his kinda stuff, can you shoot 1080p 96fps to a Atmoms Ninja 2 and get 10bit 4:2:2?

Nope the camera doesn't output HFR and the recorder doesn't take HFR, so two ''nope''s actually.

Zak 10bit looks so much better! 

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Guys, if you can read German, check out this test by Slashcam. They found that V-Log doesn't use the full amount of available color values offered by either internal 8bit recording or external 10bit recording - but reduces 8bit to 7.25bit and 10bit to 9.5bit.

In other words, it's the same story as four years ago with Technicolor Cinestyle for Canon DSLR cameras.

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Guys, if you can read German, check out http://www.slashcam.de/artikel/Ausprobiert/Panasonic-GH4-V-Log-H---Marketing-oder-mehr--63----Fazit.html#Fazitthis test by slashcam.de. They found that V-Log doesn't use the full amount of available color values offered by either internal 8bit recording or external 10bit recording - but reduces 8bit to 7.25bit and 10bit to 9.5bit.

In other words, it's the same story as four years ago with Technicolor Cinestyle for Canon DSLR cameras.

Yeah there was a thread about this on DVX user. Sounds like the info is chopped from the highlights ... so the choice is between noisy shadows or crappy highlights.

Have to say I'm very glad I didn't pay for V-Log seeing as I don't have a recorder.

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Panasonic's point was to make the GH4 V-Log 100% LUT-/color correction-compatible to the Varicam35's V-Log. The Varicam has 1 stop more dynamic range in the highlights, 1 stop more in the shadows - and in order not to require a different correction curve, those are simply left blank in the GH4 camera files.

Btw., you can easily test this yourself by shooting completely underexposed and completely overexposed video in V-Log on the GH4. The blacks will be at 30 instead of 0, and the blown-out whites will be at 190 instead of 255.

Conclusion: Don't shoot V-Log with the internal codec - unless you shoot a high-contrast subject and are ready to trade in color depth for recorded dynamic range.

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Noise is another issue/can of worms. Just test-graded someone else's intentionally underexposed test footage shot in "Standard" and "V-Log"; the camera seems to completely deactivate its internal noise filtering when recording V-Log. This is a good thing though, IMHO, because the V-Log-footage didn't have the smudging artifacts of the noise-filtered "Standard"-footage. This means that you have to noise filter in post (for which Neat Video will produce much better results than the camera's noise filter) - the same approach that Blackmagic takes with its cameras.

But there is an issue if you have noisier footage in the comparatively weak internal 8bit codec. It could overtax the codec and create blocking and banding artifacts elsewhere in the image.

Again, V-Log seems to be really engineered for external 10bit, high-bitrate recording. Hopefully, the GH5 will give us robust internal 10bit, and then V-Log will be usable in the standard package.

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Seems really polarized on how good V-log is. Lots of the beta testing was really positive. Now some people think it's not great, others think it's fantastic. Hopefully it just takes some getting used to.

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Don't

The noise really isn't bad in the shadows, it's bad in the midtones. That's where all of the ugly cyan/magenta blocking happens. Against creme colored or grey surfaces.

Your footage is among the the best I've seen in V-Log. I'm wondering if the super-sharp, super contrasty (& digitally compensated) Lumix lenses (like the 12-35 you used) help with v-log. The BMPCC certainly does best with MFT lenses for this reason IMO.

Any other evidence of this out there?

 

I'm not going to purchase the official code until I buy a recorder. 

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Don't

Your footage is among the the best I've seen in V-Log. I'm wondering if the super-sharp, super contrasty (& digitally compensated) Lumix lenses (like the 12-35 you used) help with v-log. The BMPCC certainly does best with MFT lenses for this reason IMO.

Any other evidence of this out there?

 

I'm not going to purchase the official code until I buy a recorder. 

Thanks. I don't think the lens has anything to do with it b/c I've tested some grey/beige walls with the 12-35 and the macroblocking is there, but I think the shots in Chicago were high contrast which hides it pretty well.

I've done some more testing today and have found that the Varicam LUT is just the worst in regards to hiding the magenta/cyan blocking. Something about that curve is just not right with the GH4's V Log. Film Convert seems to hide it pretty well. Exposing to the right by a stop or so also helps. Thank God faces aren't lumped into the cyan/magenta problem. They seem to be fine. I would just avoid big walls of light beige/grey, or yellow. Pure white and dark grey are fine.

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Guest Ebrahim Saadawi

it's the same story as four years ago with Technicolor Cinestyle for Canon DSLR cameras.

Even Cinestyle had none of the degrading qualities of V-Log here. S--log2 doesn't, C-Log doesn't, all in 8bit with even lower-end more-compressed codecs. 

After investigating (cool word for pixel-peeping) V-LOG on the deep image quality level (deep meaning it's way less significant for normal viewers vs. me) what I see is:

1 -More noise, shadow and midtones. Not just more, but worse looking noise pattern (coloured/blotchy)

2 -Banding, colour banding and posterization everywhere especially in the area between shadows and mids, 30-40IRE-ish

3 -A colour shift I can't remove for the life me. Neutral/Cine-D are more natural/accurate.

4 -Increased highlight DR by about a stop. Actually sees more into the highlights. 

5 -Slightly less shadow DR (clipped earlier, more noise, colour posterization/artefacts)

(benefits of v-log are in Bold)

Tested enough to decide shooting CinelikeD unless Panasonic or someone else fixes V-Log. I couldn't care less about the slightly less highlight clip.

 

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