Some comparisons: FD-1 is compatible with only TG-4 (Firmware update is required) and the TG-5.
The shooting distance is 2 - 30 cm and is usable underwater.
LG-1 is compatible TG-5, TG-4, TG-3, TG-2, TG-1. The shooting distance is 1 - 10 cm and is not usable underwater.
A interesting Olympus website is: http://cameras.olympus.com/tg4fd1review/en/ This goes into detail mostly about the FD-1, but there is a bit about the FD-1 vs.
Olympus FD-1 Review with image samples
answered May 17 '17 at 22:33