[BlindMath] Digitising technical literature with the help of the smartphone

[Niels Luithardt]

Hello,
I have a seemingly simple question:
How can I take pictures with the camera of a smartphone such as an
Android smartphone or an iPhone with the highest possible resolution?
The following background:
I would like to photograph pages from old maths and physics books in
order to digitise them. Unfortunately, there are many books that do
not yet exist in a digital version.
Professional book scanners are unfortunately not available to me.
Therefore I only have conventional scanners or the smartphone for digitising.
In order to be able to use programs like the Infty Reader effectively,
I need pictures with a resolution of at least 400 to 600 dpi.
Is it possible to achieve such resolutions with a smartphone camera
and if so, how? Do you eventually have some tips for me?
I would be very happy about any tips and hints!
Many thanks and best wishes
Niels