Trying to understand stretched vs black bars sensitivities

[spyder256]

So I've learned from this post:

 That apparently you have to account for black bars in the sensitivity calculation. Making the sensitivity higher on 16:9 on a 21:9 with black bars vs a 16:9 monitor. (38.8275 cm vs 29.0878 cm for instance)

  Whereas if you stretch that 16:9 to fill the 21:9 screen then the sensitivity can stay the same.

If the black bars are not part of the games field of view, why do they need to be accounted for in the calculation? And why does the stretch not affect things?

I'm having troubles understanding this concept.

 

[DPI Wizard]

2 hours ago, spyder256 said:

If the black bars are not part of the games field of view, why do they need to be accounted for in the calculation? And why does the stretch not affect things?

I'm having troubles understanding this concept.

If you play all your games with black bar at the same aspect ratio you don't need to account for this.

However if you play some with black bars and others in the full aspect ratio of the monitor you need to account for the black bars in the calculation.

For instance converting MDH 100% from full aspect ratio to black bars. If you want to keep a consistent movement on the monitor you would not convert the movement to edge of the full aspect ratio to the movement to the edge of the black bar (where the image ends). You still want to convert the movement to the edge of the monitor, which means accounting for the black bars.

When stretching the horizontal FOV takes up the entire monitor, so the calculations will be correct although vertical sensitivity will be different. 

As an example, CSGO with black bars should use the monitor resolution because the only thing that changes is that the game replaces some of the image on the edges with black bars. Everything basically stays the same, you just see less:

However when you stretch you have an FOV of 90 covering the whole monitor, so you need to enter the resolution you play with, and calculate a new sensitivity (if not using 360 distance, which will stay the same regardless):

[spyder256]

Okay... so what would be the correct way to convert from Overwatch 21:9 (no stretch or black bars) to Paladins 16:9 with black bars (or stretch), for example?

And this all still applies to Monitor Distance 0%, correct?

[DPI Wizard]

3 minutes ago, spyder256 said:

Okay... so what would be the correct way to convert from Overwatch 21:9 (no stretch or black bars) to Paladins 16:9 with black bars (or stretch), for example?

And this all still applies to Monitor Distance 0%, correct?

This would be correct for stretch. This is all covered in the instructions btw, under resolution.

[spyder256]

Okay so this would be correct for black bars?

If so, this is where my confusion lies, why do you need to account for parts of the game that you can't see?

[DPI Wizard]

24 minutes ago, spyder256 said:

Okay so this would be correct for black bars?

Yes.

24 minutes ago, spyder256 said:

If so, this is where my confusion lies, why do you need to account for parts of the game that you can't see?

As I said above, to make the calculations correct for your entire monitor.

For example if you convert using MDH 75% you want this:

Not this: