10 hours ago, adamhanlon said:
Compact size
Probably powered by a single 18650 cell, although AA combinations would be fine too.
Ball mount
I have been using a light that meets these three requirements successfully for my freshwater-blackwater photography lately. Very light (in more ways than one) which is important for this application. I tired a single Inon "pencil light" (3 AAs in a line) but the AF struggled. I am finding that it takes quite a few hours to charge up the single battery. As well one has to push the button a lot to toggle through off, on1, on2, SOS, and back to off. on1 and on2 are two brightness settings. The attached pix provide a better explanation than words (shot with an Ipad mini).
I am using the larger diameter Inons for scuba (groups of 3 AAs in a plastic holder). There are bunch of models with longish names. One has a 5 degree beam and the other is wide. The 5 degree light uses 3 AAs whereas the wide one uses 6 in two holders like used in the other one (but just one holder in it). It has a 3100 in the name. There is another model with 1300 in the same place. The rest of the names are identical. Inon sent the 3100 to the US dealer instead of the 1300 (what I had ordered) which has an identical body to the 5 degree light but not as versatile and powerful. With 6 cells it can go through several dives no problem. The 5 degree light is useful for spotting things during the day at modest depths in HI, e.g., 25m, where there is little color. The 3100 etc model is used for focusing. Lots of overhangs and lava tubes so needed on almost all HI dives. I have the two lights attached to a float-arm via a 3-way clamp. The other end of the float-arm attaches to the pole-cam ball in the center of my housings. I remove the two lights with float-arm as a unit for packing the housing on and off the boat (day tripper mode in HI). This makes it possible to close the bag! I mount a dive computer on the float-arm.