I don’t know about step down tines, but one way to look at emitter options has to do with the proportion of lumens to peak candelas, which should give you an estimation of flood vs. throw. Lumens is the total amount of light coming out of the front of the flashlight, while peak candelas is the brightness value of the brightest spot, so when you compare two emitters, for example the XP-L HI vs. the XP-L HD: with the HI’s 4300lm/45,000cd, most of the light is being concentrated into the central hot spot, but with the HD’s 5100lm/27,000cd, the central hot spot is less bright because more light is being diffused into the spill surrounding the hot spot.

The XP-L HI is a nice option for this flashlight. I have D4S’s in XP-L HI 3A and XP-L HI 5D, which are really nice outdoors. As others have noted, the 5D has a pleasant orangish tint, like an incandescent lightbulb. I have often bounced the light off the ceiling on my bedside table when getting ready for bed or while looking at my phone in bed so as to get some more light in the room. The beam with XP-L HI is a little tight for use indoors, though, and I have one more D4S with XP-L HD on order, which I think will put out a much more floody beam, a little better for general use.

I have a regular D4 with SST-20 4000K emitter, which strikes me as a little bit yellowish in tint. When I compare it to my D4S with XP-L HI 5D emitter, the 5D appears a little bit rosy orange and the SST-20 4000K is just pure yellow. It’s not bad or unpleasant, but I prefer the 5D tint.