How to keep same resolution for all devices without "black bars" (see game image)

I have this 3d game test I am developing. In the image below I pasted how it renders in windows phone, android, iphone. I also run in on each physical device (yes I have all the 3) and it is accurate to the unity editor.

I want to keep the same resolution than the android example for any device... I tried canvas and the following code in my research link which partially works but it keeps gaps (black spaces) running in different devices....

I thought I would never have this problem with unity, I guesses you develop your game, place your game objects in a blank canvas and this would be stretch to the host device...

I'm blind here, any comments are welcome