At Sassans suggestion I will start this one off with what is probably the most exotic hand held light meter ever made ... the SEI Photometer.
Measuring angle 1/2 deg spot and was the meter Ansel Adams used when he developed the Zone System.
http://www.rogerandfrances.com/photoschool/sei.html
http://www.kcbx.net/~mhd/2photo/film/expose/sei.htm
Don