like a bause

Hi guys, I would need some of your advice on whether when will the viewfinder/screen of x-t1 show the actual picture condition as and when we changed the camera settings. i.e. ISO, shutter speed, aperture, etc. From what I noticed, only when i changed the aperture settings, the camera will show difference in the images. Or is it only in A mode can be seen, and not the rest of the other modes.