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-   -   J-Log1 and the LS300 (http://www.dvinfo.net/forum/jvc-4kcam-pro-handheld-camcorders/531322-j-log1-ls300.html)

Duncan Craig March 4th, 2016 03:16 AM

J-Log1 and the LS300
 
I'm interested to know how people are using Log on their LS300?
Particularly in terms of operation - Correctly exposing, WB etc.

Thanks.

Noa Put March 4th, 2016 08:46 AM

Re: J-Log1 and the LS300
 
I think your only option will be to wait for Steve Mullens part 2 field report, I have been doing more tests today in my own house in preparation for that interior shoot of a pharmacy store I have tomorrow. While I prefer itu709 with some added color gain and normal black toe for weddings because it gives a nice punchy image and then I don't mind if I loose some detail in the shadows or highlights but I much prefer jlog1 for a interior shoot. I first did not understand what the main difference is but when I compare jlog to itu709 in higher contrast scenes the difference is quite obvious and jlog also looks more "cinematic" if that's the right word for it. I think I just will go for it tomorrow and shoot jlog1 and see where that leads me. I"m a bit nervous though as I"m shooting for a interior design company :) Will post the results when it's ready.

Steve Rosen March 4th, 2016 09:04 AM

Re: J-Log1 and the LS300
 
Duncan - not very scientific, but JLOG-! isn't nearly as radical as S-Log or the WDR on Canons, so I basically expose so the image looks good. I do have a Gratical with a Histogram, and I check to be sure the lump is in the middle of the range... I'm not a technical person, but with experience my footage always looks good. I also have a Spectra meter that I use if I'm not sure, or if my eyes are getting tired.

With JVC's log the image out of the camera is nearly useable as is... I basically crunch the blacks a little and dial up the chroma about +15 - +30 in FCPX.

Duncan Craig March 4th, 2016 12:12 PM

Re: J-Log1 and the LS300
 
I've always thought the same Steve.

I was wondering about the internal histogram where to best set the upper and lower indicators.
For now I've just set them at the min and max. It seems like you watch that the super whites aren't clipping, let the rest takes care of itself.

You can certainly tell how mild J-Log1 is, when you add a Sony LUT the JVC footage looks like a thermonuclear apocalypse.

Regarding what to do in post, I've found that getting the blacks down is tricky.
You can set it for one position and when the shot pans the you suddenly find you're getting crushed sub-blacks. I'm guessing this is because the gamma is so wide it's pushing the lower end around a little.

So I'm using levels instead which clamp the blacks and white, but that's not a great solution as any correction after the levels has lost that clamped information.

I guess that a proper LUT utility setup in post gets around this, as the LUT is applied to the clip before any other processes.

Perhaps until FCPX is update with J-Log1 I'll have to try grading in Resolve. Up until now I've always stayed in the NLE, but Log requires me to have a rethink. I could never get on with Protune on a GoPro either. Maybe it's just me.

Steve Mullen March 5th, 2016 01:20 AM

Re: J-Log1 and the LS300
 
Quote:

Originally Posted by Steve Rosen (Post 1910263)
Duncan - not very scientific, but JLOG-! isn't nearly as radical as S-Log or the WDR on Canons, so I basically expose so the image looks good. I do have a Gratical with a Histogram, and I check to be sure the lump is in the middle of the range... I'm not a technical person, but with experience my footage always looks good. I also have a Spectra meter that I use if I'm not sure, or if my eyes are getting tired.

With JVC's log the image out of the camera is nearly useable as is... I basically crunch the blacks a little and dial up the chroma about +15 - +30 in FCPX.

I have found the same -- I call it a "non-aggressive log." Which makes me wonder if there will be J-log2.

Steve Rosen March 5th, 2016 10:58 AM

Re: J-Log1 and the LS300
 
In this age when many are going for the (much overused) washed-out blue zombi look in color grading, J-LOG requires that you get it close to right in camera (which appeals to me a lot),

For instance, with the Pocket Camera in Film Mode, the resulting image in raw or ProRes has so much depth it can be manipulated to correct many errors from inexperience, or changes of mind. J-LOG is more like shooting film. There's some wiggle room, but it makes you a better cinematographer when you get away from the fix-it-in-post mindset.

Noa Put March 5th, 2016 04:21 PM

Re: J-Log1 and the LS300
 
Finished a shoot today and shot in jlog and it looks great, exposing my shot is just as easy as in another preset, I actually also like it as-is, like Steve said, crushing the blacks and adding saturation is already a very good starting point or even good enough as final product. I mixed it with my gh4 cine-d with saturation and contrast dialed down and both matched quite well.

Steve Mullen March 14th, 2016 01:20 AM

Re: J-Log1 and the LS300
 
In writing Part 2 I'm surprised to discover that my estimates for the correct exposure values results in an "almost ready to use contrast" the JVC supplied values yield a much lower contrast -- flatter -- image. This could mean I've been getting much less DR than is possible. So now I need to retest.

This stuff is really complicated! I know two critical issues are that log can push shadows into noise and 8-bits are really not ideal for log.

Which makes me wonder why JVC has LS300 charts that use 10-bit data. Where do they get these data?

I'll post some stuff as I write so others can test.

Noa Put March 14th, 2016 01:30 AM

Re: J-Log1 and the LS300
 
I shot the last 2 Saturdays for a client and used jlog, I exposed like I do when shooting itu709 with the zebra's set to 95%top and 90% bottom and I just set the exposure until have no zebra's on parts where I want to have detail and then I check the histogram. Everything that I shot was exposed right so I guess I"m doing it right? I used after effects to colorcorrect the footage by adding the indoor and outdoor lut jvc has supplied for this camera and it looks great but a bit over saturated so I have to tone that part a bit down if needed. Shooting log made a big differences shooting in these higher contrast scenes with harsh outside light shining inside a office space and with spots inside the room. As I understood grassvalley will be adding lut support in edius soon so I can stop using after effects which will be a big timesaver.

Duncan Craig March 14th, 2016 07:23 AM

Re: J-Log1 and the LS300
 
Noa, what ISO/Gain settings are you using?

I normally use the lowest three when in 709. The camera defaults to very high values the first time you use Log, so I set them back down to the lowest three ISOs. Then when going back to 709 I found that all three had changed to 400 ISO... Odd.

What I did find was that at 400 ISO I couldn't get the histogram reading to reach 100 IRE, in fact it only seemed to go to about 90%. From memory I bumped up the ISO to 500 and the knee kicked in about 100 and it was able to capture somewhere into super whites.

Steve Mullen March 14th, 2016 02:33 PM

Re: J-Log1 and the LS300
 
"What I did find was that at 400 ISO I couldn't get the histogram reading to reach 100 IRE, in fact it only seemed to go to about 90%."

Ditto!!!

Some camera's auto bump ISO several stops the minute one engages log. Now I need to re-read the reason why.

Noa Put March 14th, 2016 02:44 PM

Re: J-Log1 and the LS300
 
Is this not because the camera has max dynamic range at 800iso in jlog? Also when switching to log the iso doubles. I mainly used 400 and 800 iso during the shoot. Here are 2 frames from a shot outside that location I had to shoot last weekends where I shot in jlog and the same with the lut applied. I have tried to do the same in Edius with regular colorcorrection but I can't get it there so hopefully the possibility to add a lut inside edius will be implemented soon.

https://onedrive.live.com/redir?resi...nt=photo%2cjpg

Steve Rosen March 17th, 2016 10:10 AM

Re: J-Log1 and the LS300
 
I'm sorry, but I obviously haven't been doing enough research - where did you discover that the LS300's DR is best at ISO 800? Does that mean that, as with the Pocket Cameras, 800 is the native ISO of the the sensor with log?

As a rule, from my film days, I automatically gravitate toward the lowest ASA/ISO/Gain to keep noise (originally grain) at a minimum. Even with the Pocket Cameras I've found that I get the cleanest shadows at 400.

I've been shooting at 400 consistently with the 300, although I have ventured into 800 and 1600 occasionally. Since I've only shot J-Log1 since it's availability, I have no reference, but I've found 400 very forgiving in high contrast situations (i.e., exteriors in bright sun).

Noa Put March 17th, 2016 10:33 AM

Re: J-Log1 and the LS300
 
I didn't say the ls300 has a native iso of 800 in jlog, I was asking this as a question, hence the question mark at the end of my sentence.

Steve Rosen March 17th, 2016 11:18 AM

Re: J-Log1 and the LS300
 
Sorry, I didn't interpret the question correctly - so I wonder what the native ISO is...


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