unity2d fixed aspect ratio is distorted

Hello I am working on a game and it needs a fixed aspect ratio for many reasons, but I am having a problem where I change it in c# like so:

 camera.aspect = 16f/9f;

but when the screen in not 16/9 it will be distorted i attempted to fix it with:

 if(camera.pixelHeight < 1030){
 DoSomething();
 //but I do not know what to add here e.g:
 pixelHeight = screen.height / camera.pixelHeight;
 }

and if it is greater:

 if(camera.pixelHeight > 1030){
     DoSomething();
     //but I do not know what to add here e.g:
     pixelHeight = screen.height / camera.pixelHeight;
     }

the error looks like this except it looks much more distorted in the editor and player:

but I need it to look like the unity player when you select a aspect ratio like this: