I heard that 18" /45cm is about the lowest they should go. But this can depend on the LED, the strain, and all those other things.
And yes, it's a phone camera, and I actually did try that, but I have a reallllly old phone. (Phone was released in 2011 lol) I do have an Android OS though! And it works for what I need. My girlfriend has one of those big digital cameras, Nikon or Canon.. can't remember which, with the big lenses and stuff, but I'd have no clue how to work it. Which is why I keep my old phone
Tapping my screen just refocuses hm but I think I had it on auto focus? Ill have to look some more into it tomorrow and see if I can figure out this phone lol