AKH

You're seeing exactly what you should be seeing.  It's just that with ungraded log material it will be more obvious.  Parts of the image with plenty of light will not suffer from noise.  Other parts of the image that are low light will show noise unless noise reduction is applied in camera.  This is just the physics of the situation.
To see less noise without using noise reduction, you have to increase exposure (more photons hitting the sensor).

The info out there is a bit contradictory, but I've not found a way to directly enter a Kelvin value on my D5300.  The cool white fluorescent WB setting should be a Kelvin value of about 4200 and that can be fine tuned either way.

For those who haven't seen this yet, and have a large enough bank balance:
http://www.cookeoptics.co.uk/u/news.html?Open&v=99&c=2&y=99&d=928A82023974CE1A85258020005E3972

That would have to be altered in FCPX, but I'm not familiar with it.  With a 4K timeline you should be able export a short clip in Rec.2020 to test on Youtube.

If I was to hazard a guess, I'd think you've got a colour space conflict.  Youtube might be expecting that 4K uploads are in Rec.2020, but I don't know.  I couldn't find any recommendations about that.

This seems to be gaining some momentum in online media.

https://www.youtube.com/watch?v=xcVpWMfEdB0
http://www.thedailybeast.com/articles/2016/03/08/america-s-largest-indie-photo-store-b-h-sued-for-segregated-bathrooms.html
 

The Sigma doesn't have completely constant transmission across it's focal length range.
 
http://www.dxomark.com/Lenses/Sigma/Sigma-18-35mm-F18-DC-HSM-A-Canon-mounted-on-Canon-EOS-700D---Measurements__870
 
Would the speedbooster make it more noticeable? Not sure.

For Premiere 5.5 I would right click on the footage in the project window and select Modify -> Interpret Footage.  Make sure framerate is set to 25fps and Field Order is set to No Fields (Progressive Scan).
 
Hopefully that will be enough clear the problem.

For Premiere 5.5 I would right click on the footage in the project window and select Modify -> Interpret Footage.  Make sure framerate is set to 25fps and Field Order is set to No Fields (Progressive Scan).
 
Hopefully that will be enough clear the problem.

I'm guessing it is a setting relating to monitor display over HDMI to avoid playback jitter on screens that support 24Hz.
 
 
Edit: It also seems that according to current standards 4K can only be transmitted over HDMI at 24Hz, whereas UHD can/will go higher in the HDMI 2.0 spec.
 
Edit2: Having looked at the GH4 instructions, 24Hz (Cinema), 50Hz (PAL) and 59.94Hz (NTSC) are just system frequency settings to keep recording framerates divided into their specific regions.  4K records at exactly 24fps (only available in 24Hz mode) whereas UHD can record at 23.98fps, 24fps, 25fps or 29.97fps depending on what the system frequency is set to.

On the snipers, it isn't so much the fact they point out an error as the sheer hatred and bitterness in which they do it. I don't want a forum full of people like this, therefore both users have been banned permanently.

ISO is an analogy for the sensitivity of film stock. The use of this term is *helpful* for estimating the relative sensitivity of a sensor with a certain gain chosen. But actually vague and incorrect. Native ISO means the signal is neither amplified nor attenuated.

One thing to note.  ACR applies sharpening by default on dng files.  So if you haven't zeroed it the noise does get lifted a bit.

One thing to note.  ACR applies sharpening by default on dng files.  So if you haven't zeroed it the noise does get lifted a bit.

One thing to note.  ACR applies sharpening by default on dng files.  So if you haven't zeroed it the noise does get lifted a bit.