What is the equivalent of ISO100 in Blender's Color Management Exposure?

[Eary_Chow]

Blender’s exposure is the universal exposure stop value:

2^stop_number * middle_grey = actual_value

for example, exposure value of 15 with middle grey of 0.18 is 5898.24:

The inverse of the formula:

log2(actual_value/middle_grey) = stop_value

e.g. log2(5898.24/0.18) = 15

@thinsoldier

I’m pretty sure Aperture, ISO, and Shutter are variables created by that addon

When you are dealing with real life camera, all three of these affect your exposure, ISO is just one of the factors, so ISO 100 is not enough to know the corresponding stop value. You need to know the other two as well. I believe most phones have fixed aperture (I think it maybe included in some phone photo’s metadata, you can look it up), and you already get the ISO, so you now you need to figure out what the phone camera app’s shutter speed is set to, and follow the formula posted.

@Hikmet

( Log2( (100 * (Aperture * Aperture) / (ISO * (1.0 / Shutter))) ) * -1 ) + 9.416

@thinsoldier

I finally found a camera app for my phone that shows me exposure values

BTW it is better to modify the shutter speed than the ISO when boosting exposure, ISO is software-calculation whereas shutter speed is physically exposing more lights to the sensor, therefore increasing ISO can lead to noisier image comparing with slowing the shutter speed a little.