Before July 1912, the original copyright holder was the creator of the photo, i.e. the photographer. Surely not a surprise.
However between July 1912 and July 1989, the original copyright holder was the owner of the material on which the image was taken, i.e. the negative. This could be a corporate body such as Magnum Photos. So the creativity in taking the photo no longer mattered!
Fortunately, for the photographer, since August 1989 copyright law again regarded them as the creators, and therefore the original copyright holders.
Copyright is never as simple as you think. If you don’t know the date of the photo, you might be trying to trace the wrong source for permission to reproduce the image.