What's the difference between lumens and candelas?
Lumens measure how much total light a flashlight produces whereas candelas measure the amount of light that shines in a single direction.
Looking at the Fenix PD36R and the Fenix E30R, both of these lights have a 1600 lumen output. However, the PD36R has a candela rating of 19,977 candelas and the E30R has a rating of 10,302 candelas. The PD36R features more of a hotspot while the E30R features more of a widespread beam which is why the PD36R has a higher candela rating.