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| 30 Degree Grid for 28 Deg Long Throw Reflector??? http://www.paulcbuff-techforum.com/viewtopic.php?f=8&t=2500 |
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| Author: | shutterbugm [ Thu Nov 10, 2011 10:00 am ] |
| Post subject: | 30 Degree Grid for 28 Deg Long Throw Reflector??? |
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! |
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| Author: | Technical Support [ Thu Nov 10, 2011 10:32 am ] |
| Post subject: | Re: 30 Degree Grid for 28 Deg Long Throw Reflector??? |
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. |
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| Author: | tetrode [ Fri Nov 11, 2011 10:45 pm ] |
| Post subject: | Re: 30 Degree Grid for 28 Deg Long Throw Reflector??? |
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. |
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