... I've seen photographers in split fins and if they have floppy tips on their split fins they can easily contact the bottom without the photographer even being aware of the position of the tips of the fins...
I dive regularly with several very experienced divers who wear Biofins (heavy split-fins), and they really have a hard time hovering in photo situations without their fins migrating downward and kicking up silt/sand. Since they provide very little thrust at "stopped" speeds (i.e., when you're not swimming), it seems easy to unconsciously keep kicking with little apparent result. I don't know about other split fins - those that are wider (have more flat "fin" surface area) and aren't as heavy might be less of a problem. I'll stick with my Force Fins, which are VERY effective in tight spots with little kicking - just slight flicks of the fin with knees bent.
As I stated long ago (when both I and this thread were much younger
), I use two different pairs of Force Fins - Tan Delta's when I don't anticipate ripping currents (e.g., Caymans, Lembeh, etc.), and the longer Tan Delta "Extra" Force Fins when I expect lots of current (e.g., Cocos, Galapagos, Komodo, etc.). They may look funny, but I haven't seen anything easier on my feet (no blisters), my legs (little or no cramping because all the thrust/pressure is on the downstroke where leg muscles are naturally stronger), and functionality. If you are on at trip with someone who has FF's, ask if you can trade fins with them for one dive to try them out; I do that with people all the time.