Exposure compensation in filmic V4

[Jade_NL (Jacques)]

@Egocentrix

That’s odd, and 0.83 is very specific. I would imagine the exposure factor would depend on the camera and its jpeg settings (and how they fudge iso values)

Gave my search for this 0.83 that’s in my head something extra and found it again:

filmic v4 on the way

Since that message, I have come across some data that seems to support the +1 EV. First, some background: ISO 12232:2019 defines various ways to compute an ISO value. Out of those, CIPA mandates the use of either SOS (Standard Output Sensitivity) or REI (Recommended Exposure Index), which are computed as \frac{10\,\text{lx}\cdot\text{s}}{H} where H, for an average scene, is a mid-tone exposure. More specifically, for SOS on a camera that produces 8-bit output, H is the exposure required to pro…

The last paragraph:

That means that for a shot metered by an average camera (as of 2014), to get 100% reflectance at 100% in the RAW and 18% reflectance at 18 %, we need to apply +0.83 EV to the RAW values.

As always, Aurélien’s above reply is spot-on.