How To Confirm Alexa Footage is LOG-C?

[Craig Harris]

If you are timing with ProRes444 from the Alexa, there won’t be any meta-data that comes embedded in the file like you get with RED. You’ll know simply by looking at the footage if it’s Log-C. Other than that, the best way is to communicate with the DP, DIT & production manager regarding your project.

Craig

[Nate Weaver]

It won’t be higher than 65IRE or lower than 10IRE on the scopes without a LUT, I can tell you that.

Nate Weaver
Director/D.P., Los Angeles
https://www.nateweaver.net

[Sascha Haber]

True, also loading one of the LOG-C luts from the Alexa Lut builder will show if it jumps into place and looks nice and crisp or clipped and overcontrasted

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[Illya Laney]

If there is a way to tell, there would also be a way to know if it’s Rec 709 and not LOG-C.

Are you trying to organize footage based on that? If you’re doing dailies, you should try and request that info from the DIT or have them put it on the camera reports. If they’re changing from 709 to LOG, I bet they’re doing it between camera rolls or scenes so you could sort it out that way.

If you’re onlining, request that info from editorial, so you’ll know if they applied LUTS during the transcode or while they were working with the footage.

twitter.com/illyalaney

[Jay Lee]

Thanks guys.
Yes we are trying to organize footage based on LOG-C / Rec 709 however in such away that it does not require actual loading and viewing in Resolve to determine. Kind of blown away that this kind of critical information does not appear in file headings, meta data etc??

cheers

j

[Illya Laney]

Ingesting some footage right now and I see there’s some info in the XML. It’s going to be in the first comments section under logginginfo along with all the other data like Asa and Fps.

twitter.com/illyalaney

[Neil Sadwelkar]

The XML file that accompanies the Quicktimes carries information on the ISO, temp, and other such data. It is human readable and if you pore over it you can find this info.

———————————–
Neil Sadwelkar
neilsadwelkar.blogspot.com
twitter: fcpguru
FCP Editor, Edit systems consultant
Mumbai India

[Jay Lee]

Nope…not these XML’s. No mention of ISO or other data?? We’re seeing references to ‘time-code’, ‘Logging’ ‘Reel Numbers’ etc. only

j

[Neil Sadwelkar]

I just opened one XML I got yesterday. It has one Master Comment field that goes…

SensorFps:24.000,ShutterAngle:180.0,WhiteBalance:5600,CcShift:0,ExposureIndex:800,Gamma:LOG-C FILMMATRIX

So these Quicktimes are logC. When I import the XML into FCP I see this in the Master Comment 1 column.

———————————–
Neil Sadwelkar
neilsadwelkar.blogspot.com
twitter: fcpguru
FCP Editor, Edit systems consultant
Mumbai India

[Jay Lee]

What firmware was that camera running Neil? Fine tooth combed our XML and it contains no such data.

cheers,

j