For camera scanning I have a "copy stand". I bought it 20 years ago for $175.
It has a camera mount on a counter weighted system that allows the camera to be moved up and down and then locked into position.
Two color correct lamps are fixed to either side at 45 degree angles. I clamp the book's cover to the copy bed and then position a glass plate over the book.
I let the camera's auto focus deal with the varying height of the book as the pages are flipped.
This is a vast improvement over how it used to be used when i first got it: Panasonic CCTV with a manually rotated color wheel into an Amiga.