Adjust screen size without expanding camera view

Hi I'm getting close to launching a game but I have a problem.

I need to make it so that what is displayed by the camera in the unity editor
scales to different screen sizes/resolutions. for various devices.

what's happening in my build is when I adjust the screen size, the camera shows more of the scene.
What I want instead is what is shown by the camera in the unity editor to scale to the screen size adjustments.

Does anyone know how to do this?

 

thanks i'll take a look at it in the morning

 

It was just what i was looking for thank you