Here is a nice little trick I learned recently.
My daughter shot a nice buck and it was getting dark fast. I hate the flash on the iPhone so I put the phone on the ground while I laid down (with the phone on the ground it is much steadier). Then, I held a spotlight on the buck and her face. The light has a dim mode which I used and it covered most of the deer and hunter just fine.
The iPhone camera picked up just enough of the available light from the sunset and made a nice hero shot from the hunt.