Change format for external drive?
I recently installed a 1 T external drive to my MacBook Pro Mojave , purely for storage of scanned memorabilia of different types, mostly photographs. It is partitioned into six volumes into which I direct scanned images according to choice of personally-chosen category and to date have stored several gigabytes in each of the volumes. I don't know why I chose to format the drive as Mac OS Extended but now, from my research of Apple information material, it seems that APFS would have been preferred, with features not available to me. Do I correctly understand that APFS would give me preferable options as to flexibility of capacity in the various volumes? and can I now change the format to APFS without loss of stored images?
MacBook Pro Retina