SD card DCIM folder shows empty in Finder

When I try to access photos from an SD card using Finder, the DCIM folder shows the camera subfolder, but that folder shows no contents. Disc utility shows approximate size of space used by photos on the card. I am using Monterey 12.4 on an M1 Mini. I have tried several card readers on different ports, and can see the contents 1. on my camera, 2. using a card reader on my iPad, and 3.) by importing to my mac by using Photos app, so my problem seems to be with Finder. This is a new problem that showed up out of the blue--worked fine a few days ago. Suggestions welcome with thanks in advance.