a trip to Brazil in Oct prompted another hunt for a flashlight powerful enough for night focusing at 100 feet or so
tried a 100 lumen Surefire a year ago that could almost but not quite do it
found the Fenix TK11 rated at 225 lumens (high mode) which has a tightly focused central beam nicely matched to 400-600mm lens with quite a bit of spill light as well. It works. 5 1/2 inches long with a 1 inch body and 1 3/8 dia reflector - incredible. 1 1/2 hours from 2 123a lithiums on high, 10 hours on normal.
$75 from pst-flashlights.com
advances in LED technology are amazing