O7Q black tint changes when changing FS700 ISO

[Martin.G]

So i just noticed tonight that 4K cDNG and 4K2HD in S-log 2 gives me a tint change when i adjust ISO changes.

At 2000 ISO the whitebalance and blacks are fairly red, still a little more greenish than the onboard LCD and the actual finished product.

But when i change to 3200 ISO (or 6400) the tint in the blacks go sickly greenish. Not true green, but a slight green tint. When changing back to 2000, shadows noticably go more red. This change goes through into the recordings, so changing ISO when running and gunning is very tricky for the colorist later on.

The internal AVCHD is to my quick test and check on the PC unaffected.


Is this normal behaviour? Seems kind of odd.

 

[Mitch Gross]

When you push the ISO, especially when you push it up so very high as you describe, you are boosting the color channels. In particular the green channel as it has twice as much available information within it as the red or blue. So on extreme exposure pushes you can have a change in white balance.