What camera were you using for the example pics?

Parallax correction basically works by having framelines in the viewfinder - which move towards the lens the closer the lens is focussed. So this "corrects" parallax, or more accurately compensates for it in the viewfinder.

Many older RFs without compensation simply show less of the image than there is actually going to be, this helps minimize cutting things off due to parallax - but also means sometimes you get things in the edges of the photo you didn't count on!