Exposure and brightness control doesn't work properly

[Twist]

Hey. I found out just now that the exposure and brightness control doesn't work properly. Please see the attached images.

[yolov]

Thanks! I'll need to check our maths, but so far it seems Player matches the VFB for exposure, and then Nuke does something different.
Can you tell me how you're doing "brightness" in Nuke?

[asen_stoilov]

Hi, we are probably using different formula for those corrections.
The formulas are:

exposure: channel_value *= (2 ^ exposure_value_from_ui)
brightness: channel_value += (brightness/1000)

Regards,
Asen

[Twist]

Hi, we are probably using different formula for those corrections.
The formulas are:

exposure: channel_value *= (2 ^ exposure_value_from_ui)
brightness: channel_value += (brightness/1000)

Regards,
Asen

But how is it usable then, if it doesn't properly?

[yolov]

Originally I thought it was because nuke may be doing something different that Player and the VFB and I wanted to pull out what formula we're using for exposure.
It seems that 2 ^ <exposure_value> is the common approach.

After some more digging, it seems that nuke's exposure node lets the user adjust the exposure in a few different units.
2 ^ <exposure value> is for adjusting in f-stops. So changing 'adjust in' from the default 'densities' to 'stops' and entering the same value in player and nuke will give you the same result.

I'm using the exposure node in nuke, thinking you're doing the same. Correct me if that's not your setup.
Here's an example: