There are apps to use your phone as webcam, i use Iriun, so that's one more app you could try.
If you play commander (and I think you ould use itfor other formats as well), you can use Spelltable.com. It has an build-in option to use your smartphone as a camera and it has a card database alsobuild in. Even if the 'point and search' option doesn't work you stillcan search for thecards your opponents played, so youcan read them better than on screen on thebattlefield.