New DO forum user, but very OLD DO user.
For roughly the past four years, since I've had a digital camera, I've been using a small program called Siren to rename the photo files, using information stored in the tags (namely, the date and time the photos were taken). It is very flexible, with a wide variety of options. There are other programs out there like it, but I haven't compared Siren to any of them, since it pretty much does what I need.
I just noticed, while renaming some other types of multiple files with DOpus tonight, that it now provides options to rename files using tag data. I played with it a bit, but for my purposes, it doesn't fit the bill, primarily because DOpus uses the shooting date and time tag info as is (e.g., "25-May-2006 13_09_36"), whereas Siren reformats it into something more practical for filename use ("20060525_130936"). I wonder if you were planning on fine-tuning that feature in DOpus?