I have been following the "Comments" for the video and I think that the discussion has clarified the situation.
First the short answer is that yes, changing the Gamma itself and nothing more will "change" the content of the raw. But it is not as significant as it sounds. The change is no more that what results from changing the ISO appropriately.
The short description of what is happening and why is like this:
First, the changes to the Gamma are limited to applying the Gamma from some of the available VIDEO profiles in the cameras. That is to say for example, you set and use the Gamma from the "Slog2" video profile for still pictures. If you do that, then the camera "re-scales" the ISO to give appropriate exposure to your picture.
So when you nominally set ISO 2000 in under "Slog2", the camera is acting as if you set a different ISO under the normal Gamma. It also probably sets parameters to tell a processing program how to handle the image data, but the resulting image data in the raw file will only reflect the change in the exposure.
Possible Justifications:
The question of why this "capability" is provided has a sound theoretical base. There are two ways that a photographer who is involved with video production might find this useful. First, if you are "scouting" then taking the pictures with the camera set up like a video camera can help predict how the
final video recording will look when it is all processed. It might also help provide guidance notes to the camera crew and anyone doing post processing.
The second possible advantage is that if you take still pictures that might be included in the final production, the "look" and the processing could better match the rest of the video in which they are incorporated.
Is it "a big deal?"
Probably not that much.
At the front end of the production cycle, scouting shots do not really have to resemble final production that much. I cannot say more than that because different producers, directors, etc. will have their own point of view on the matter.
As far as "included" stills are concerned, editing software can generally treat all the "objects" (video clips or still images) individually. So a still image is processed with its own adjustments which will not have anything to do with the previous video clip object or the following object.
Outside of Video Productions
In the case of someone just interest in taking still pictures outside of any "video production" situation, one might as well just ignore this stuff. It will not help you get better pictures.
See:
'PXW-FS5 Official Tutorial Video #1 "Picture Profiles" | Sony Professional', Published May 29, 2016, "Sony | Camera Channel",
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Also See:
"Why are Sony’s ISO’s different between standard gammas and log?," by alisterchapman, published [URL='http://www.xdcam-user.com/2017/09/why-are-sonys-isos-different-between-standard-gammas-and-log/']September 10, 2017, XDCAM-USER.COM[/URL]
"[URL='http://www.xdcam-user.com/2017/09/why-are-sonys-isos-different-between-standard-gammas-and-log/']Why are Sony's ISO's different between standard gammas and log? | XDCAM-USER.COM"[/URL]