This is my current micromineral photo setup. The camera is a Canon 90D with a Canon 70-200 mm zoom as a tube lens. I use a Mitutoyo 5X or 10X M Pan APO objective. The 5X gives a 4 mm FOV, the 10X a 2 mm FOV. The camera is attached to a Stack Shot rail which is computer controlled. I use .015 mm steps for the 5X objective and .005 mm for the 10X objective. I use the control module in Zerene Stacker to set the step size, start point, end point and dwell time between shots.
The resulting images are imported to Lightroom for minor processing and then exported to Helicon Focus for stacking. Final processing is in Topaz AI and Photoshop.