Anyone know if there is a way to........

I have 2 drives with thousands of files scattered on them over time.
Is there any way to find duplicate files easily.
For example, is there any software in which I can select a directory containing a number of files on Drive 1 and then check all the directories on Drive 2 to see if any of the files in the directory selected on Drive 1 exist anywhere on Drive 2.

A little late, and it might not be as well known, but I've had good success with Czkawka in the past when tidying up:

GitHub - qarmin/czkawka: Multi functional app to find duplicates, empty folders, similar images etc.

Fast Duplicate File Finder from Spunk's link is good too.

Considering that it is photos that I need to sort out, having looked at all of the options I settled on Alldup as the best for this exercise.
It lists the duplicates and also shows previews of them to compare - so I know exactly what I am deleting - and it also allows me to select multiple items for deletion at the same time.

Some of the others could prove useful in the future though.
Thanks again.