Adjust 2d (orto) camera on game start / window size change

Hi there. 1st sorry for my fail english.

Making a 2d game and need my camera to capture exact widht from screen without fixed aspect ratio
like here:

Problems:

1 - camera calc wrong aspect ratio (not! fixed in camera settings) - it is always 1.33

2 - after scale it save correct widht, but goes wrong vertical position like here:

possible solutions:

a) can some on say how to handle vieport size changed event so i can adjust my camera there

b) i can grab vieport size (like for log) every tick of game and check is it same as before, but problem is - tip says not to do it

Can some one help me how to make it correct?