What I was trying to say is that it should. Whether using a perspective or orthographic camera it should always do exactly that.
So one or more of the following are probably not done correctly:
- The boolean is not set properly in your spawn code
- You are not actually rendering at 1920x1080
The first is easy to check: simply pause and eject in the editor and select the spawned camera to see if it’s properly set. However, the issues you are describing with stretching in full screen seems to indicate that the issue might actually be that you are in fact not rendering at 1920x1080 at all. Because (I’m asuming 1920x1080 is also your screen resolution here) you should then not see any stretching whether constrain aspect ratio is on or not, regardless of the FullscreenMode.
To be able to help further you might want to post some images of what you have now and the code you are using to set both your camera and screen resolution.