Phone cameras can often see into the IR spectrum, but by now most of them are able to deal with that properly to make the images look normal. I remember some 3MPix phone camera from like 2008 that created strong purple coloring for example with camp fires, especially if you took images of the embers (also with BBQs if done with charcoal). Just hold an IR remote and press a button on it and see if your phone sees the IR LED light up. My current smartphone sees it clearly. No idea how far into IR the A7s sensor without the IR filter goes; with IR filter it barely registers my IR remote (I have an unmodified A7s). It also depends on the glass/lens.