Hello, according to your case, you can recover your photos with the fixes below. You should know there are many software for recovering data for SD cards on iPad and Mac:
(1) Try data recovery on Mac. iBoysoft Data Recovery for Mac is a good choice to try, which can help you recover all deleted files from the SD card.
(2) Try data recovery on iPad. You can try some effective apps like PhoneView to ensure a safe recovery on your iPad.
Maybe recovering data on Mac seems more convenient for you, hope that you can find all the data at last.