noise (profiled): confusing description of "adjust autoset parameters"

[grothesque]

The relevant manual section says:

In general, the value of this slider indicates the number of stops by which you had to increase the exposure. For example, if you had to push the exposure 2 stops above what you normally use, then set this slider to 2.

This confuses me to the point that I do not understand what this phrase is trying to say.

The default value of this setting is 1. Taking the example of exposure pushed 2 stops above what one normally uses, I could understand if the slider had to be set to 4 (if its scale is linear), or to 3 (if it's log2).

But 2? That's consistent with square-root-of-linear, but if this parameter indeed works this way, the documentation should be more explicit.

[elstoc]

Thanks @grothesque.

@rawfiner please can you advise on this.

[rawfiner]

Good point. The message conveyed should be 2^(number of stops added), which gives 1 if no exposure compensation is done

[grothesque]

Wow, you guys are responsive...

[elstoc]

Thanks @rawfiner - I'll update it

[elstoc]

@rawfiner - Edit sorry try again

In general, the value of this slider should be set to 2^(exposure compensation) where exposure compensation is the number of stops by which you had to increase the exposure. For example, if you had to push the exposure 2 stops above what you normally use, then set this slider to 4.

?

[johnny-bit]

I wonder if adding another example, eg -1 ev and resulting correction of 0.5 would nail that this is 2^(exposure comp)

[matt-maguire]

Or else we forget about stops and just say that the "effective ISO" used by the denoising algorithm is the actual ISO multiplied by the slider value. The higher the "effective ISO", the more aggressive the denoising parameters will be set.

[rawfiner]

I like @matt-maguire proposal. I think it is clearer