We have Sony_S3C_Slog3-SG3.Cine ro LC-709 lut installed - which I believe is a 3D cube.
Question is, as it is a cube - do I really have to remove it for grading? - or does symphony place it at the end of the pipeline to look up values for each channel to conversion @ 709? (we are currently in v. 8.2.11)
We are using the CT applied for editors and rough cuts for obvious reasons.
As far as I know there is no way of just toggling the LUT in v.8.2.11 without actually deleting the CT from source and then refreshing color adaptors in a master sequence (which is what I currently do) - I was wondering if there's really a need to delete the CT from the source files before grading, if it's applied after the color transform from Symphony tools - my logic is that I'm still just looking thru a LUT at 709 on my monitor, or do the Symphony tools actually use the 709 transform as the base for correction before going into 12 bit RGB? YUK.
ie. is the LUT applied to the end of the stack - or at the beginning.
I'm guessing for grading, those clever people at Avid would logically have it at the end of the stack, even though it's referred to as a 'source setting' - but I'm not sure at all what's happening.
From what I understand if the LUT is applied as a source setting it is applied before any colour correction. This means that any limiting caused by the LUT is locked in and cannot be recovered by the colour correction However, using the LUT effect from the effects pallet, you can apply the LUT post correction on the timeline.
I believe some people remove the LUT from source and just grade manually the ensure you can use the full range. Does anyone have any colour correction presets that emulate the LUTs as a start point?
As a separate issue / question I have been given footage shot on an FS7 Slog3 which looks awful whatever I do to it! Faces have purple hue and colours are not great. Does Slog change the colour matrix at the same time as the luma curve and I have the wrong LUT or has the camererman screwed up using the wrong matrix?
You need to know which Slog profile that was used in the camera - these are totally different colorspaces than REC709. It's not just luminance.... Check this link.
http://community.sony.com/t5/F5-F55/S-Gamut3-vs-S-Gamut3-Cine/m-p/446476
as far as Slog looking bad in Composer - I have issues with transcoded material from FS7 that goes to 8bit codecs such as XDCAM. Banding and color artifacts all differ, eg. from AVC-i 10bit to XDCAM looks ok for banding - but SLOG.Cine3 to XDCAM has pronounced banding and I noticed a shift in the black too that I'm going to have to look into also. It all seems to depend on which part of MC does the transcoding from what - rendering or videomixdown to XDCAM does not look the same as transcoding to XDCAM via the ingest tool in the case of SLOG. I don't have specifics yet, but it seems as if there's a problem here on 8.2.11.
I can fix it by working native, of course, or by transcoding to a 10bit format like JP2K or AVC-I - videomixdown of these to XDCAM does not produce the same banding artifacts as ingest from AMA does.
There are several threads about this on here.
Hi! And them...which is the best method for edit slog-3 footage from fs7 in Avid Actually 2018.3. At this moment for me only works first, transcoded in Catalist Browser and them consolidate the ProRes files, only at 2K whit the free version of Catalyst. Any other option.... for work whit slog-3 at 4K....Resolve...? Thanks.
MC 2018.3 iMac 27" 3.5 GHz i7 32GB RAM
With my GH5 I found out the best LUT to start with is ARRI ALEXA LogC to 709.
I am always transcoding clean. I mean with VLog-L without the LUT at source settings.
Then the first thing I apply is the LUT and afterwards I make more corrections in Symphony.
Always start with the LUT then anything else.
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But I think, there are many diferences whit the AMA plugin, I use for XAVC Sony a nablet plugin for Sony, so the footage it´s not good when apply the plugin, appears a lot of pixels and banding, but when I viewing in Catalyst ( Sony software, the footage it´s correct, good exposition, etc... Thanks for your comments.
Gretski:Does anyone have any colour correction presets that emulate the LUTs as a start point?
I have always wanted something like this. I tried creating a basic SLog3-to-REC709 color correction and saved as a CC pre-set, but I never came up with anything close to universal.
Gretski:As a separate issue / question I have been given footage shot on an FS7 Slog3 which looks awful whatever I do to it!
When shooting Slog3 on the FS7, you still need to select from one of three color correction pre-sets. One is 3400K and the other two are daylight color temps. Maybe the cameraman never adjusted this. Even though you are going to color balance SLog in post, it's best to select the closest color temp pre-set when shooting. Since you can't white balance off a card when shooting SLog, I always shoot a couple of seconds of a balance card for each scene. Then removing the color cast in CC gets you very close in terms of color balance.
I have a fantastic editing assistant. He stays by my side when I edit...doesn't talk too much...and thinks I'm a genius! Check him out here: www.youtube.com/watch?v=ZQVkYaaPO6g
One of the big issues is that the Avid color correction engine (MC or Symphony) is NOT based on 32bit processing. This type of math can allow recovery of levels that have been clipped by the processing of the color corrector (not if they were clipped in camera).
This is important because LUTs can clip info. With the very basic color pipeline of AVID, once the color is clipped it is gone. Therefore the desire as noted to not use a LUT and start from scratch with LOG based footage.
I have no suggestions other than possibly shoot a high quality color chip chart under proper color temp lighting. Use this with and without LUTs and an eye on the scopes to try and create your own base color correct to use rather than a LUT.
Or spend $995 for Baselight Editions and leave the '90s behind.
JEf
_____________________________________________
Jef Huey
Senior Editor
jef:Or spend $995 for Baselight Editions and leave the '90s behind.
Dave S.
jef - agreed! Symphony CC was revolutionary when it was bought out but nothing has been improved or changed over the years. ( I bet nobody is left at Avid who knows how it works!)
The fundimental point of Slog is to allow greater dynamic ranges and it is entirely lost if the LUT is pre applied and burnt in before CC takes place.
Gretski and jef
Let me check with Luc.... he might know and I can dig through my files and see what I can recall as well.
Marianna
marianna.montague@avid.com
DStone: Or get the free version of Resolve and round trip using AAF files (not always the best solution; you have to learn a whole new system in order to do your color correction and work between that and MC.
IMO the learning curve for CC in Resolve is little different from the learning curve required for CC in Baselight.
Symphony is still fine.
I find the best practice to correct after the LUT but if someone wants, can make the corrections first
and then apply the LUT.
Correct me if I'm wrong but I believe a LUT must be applied before any correction because it is designed to reverse the slog curve from the camera. If correction is applied first, correction curves will not work as designed.
If the LUT is applied first and the camera is using the full range of Slog it WILL clip the highlights / lowlights. Because of the signal processing, Symphony cannot recover those clipped values, the information is lost.
Isn't that what I already told twice?
I am applying the LUT first and then I CC.
With my GH5 what I see is perfect.
Who says that Symphony can't revocer the shadows highlights?
Or even the simple CC of Media Composer?
P.S. I also have (as a beta tester Baselight).
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