Phones can do just about anything, but they can't change the laws of physics, and they just use fuzzy logic to produce pretty pictures, assuming that everything about the picture is standard, normal and average. And there's nothing standard, normal and average about making an underlit background look properly lit.
Here's an extract from my beginner book about mobile phones. Not much detail there, simply because the book is about photography with real cameras.
"But why buy a camera at all, when you already have a smartphone? Well, the great thing about smartphones is that most of us have one with us all the time, and having a ‘phone in our pocket when we want to take a shot beats having a large, heavy camera that’s sitting at home – but there are some major problems with smartphones.
Firstly, the camera side of things is extremely basic, but the software side is brilliant and, to a large extent, makes up for the camera limitations. But the clever software often substitutes real elements for fake ones, putting in detail that the camera missed, and often getting it wrong, For example, some phones recognise the moon when it’s in your photo, remove it and replace it with its own stock photo of the moon. This may be OK if your photo does include the moon, but not so good if it thinks that the football in your photo is the moon . . .
And secondly, the clever software, which includes sophisticated artificial intelligence, does everything for you, taking all control away from you. Apps do exist to allow manual control, but they have limitations.
And, without that control, you can’t learn to improve your photos. And that’s why you need to use a real camera to learn with, even if you also use a phone.
And, in bright sunlight, it can be difficult to see the screen.
And phones are entirely the wrong shape to hold steadily, unlike actual cameras, which have an ergonomic design that makes it easy.
I’ve used my iPhone quite a lot for this book, taking close-up shots of (mainly) the screen on the back of one of my cameras, which it should be perfect for – but, although all of these shots were taken in the same place, with the same lighting conditions at the same time, the colours vary a lot, all of the images have unwanted reflections and some of those reflections, especially of the red phone case, are horrible."