Paul C. Buff, Inc. Technical Forum

So...I am trying to understand how the 11 inch Long Throw Reflector which has a 28 degree spread would benefit from a 30 degree grid? It almost seems like a trick question.

So is the 30 degree grid diffusing the light an extra 2 degrees?

Thanks!

Beam width is defined by center readings out to -1f. Beyond the angle of -1f you can get feathered edges. Some modifiers have a very sharp cutoff from -1f to virtually no light (like grids), while some have more gradual fall off, like bare reflectors (which will vary from style to style). The 11LTR has a fairly sharp cutoff, but not as sharp as a 30d grid. Adding the 30d grid to the reflector, you still get a 28d beam spread (as defined above), but the feathered edges are limited to 30d to give you a sharp cutoff.

I don't own the 30-degree grid but here's a comparison of the 11" reflector bare and with the 15-degree grid:



The reflector was positioned about 4 feet from a white background. The Einstein was set to -6 stops and still the lens had to be closed to f/22 (ISO 200). The 11" reflector puts out lots of light.

Dave F.