It's easy to do with a smartphone and you usually don't even need a calibration object. A software like Metashape or Meshroom can infer the lens transform and p

It's easy to do with a smartphone and you usually don't even need a calibration object. A software like Metashape or Meshroom can infer the lens transform and position of the camera from enough photos of the same object from different angles. The small smartphone optics actually help you by giving you a deeper DoF. Not the best example but this http://koanlabs.org/vignettes.html http://koanlabs.org/vignettes.html rock is ~5 cm tall and my best guess is the minimum detectable feature size is about 10 microns. EDIT: Sorry to be clear the definition of easy here is "as easy as most photogrammetry", to get good results you will universally do a lot of knob twiddling, waiting and cleaning up broken bits of mesh unless all you do is scan rocks. Scanning rocks is easy.