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bouncing light


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#1 Daniel Madsen

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Posted 08 April 2007 - 02:14 PM

I am aware that by filling a bead board with light (at which point the bb becomes the source) greater light output results than if you just spotted the light on a small section of bb. Wouldn't it make sense though that if you spotted the light into the bb, the bounced light would maintain its intensity for longer? I understand the working practice. I?m more concerned about the science.


How about this one.... what would result in more light output? Placing a light next to a bb so that only a small section is illuminated or walking off the light, furthering the distance between the light and the bounce and thus the subject but having the bb filled completely with light.

Danielle.
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#2 Alex Haspel

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Posted 08 April 2007 - 03:24 PM

higher light output is not the result.
the actual "source" is bigger, so the light hitting the object appears to be softer.
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#3 Daniel Madsen

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Posted 08 April 2007 - 04:07 PM

Of course higher output is not the result of using a bounce board. I am wondering why more light is "bounced" when a white surface is filled completely with light rather than just partically.
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#4 Michael Nash

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Posted 08 April 2007 - 05:14 PM

If the beadboard is lit to twice the brightness over half the surface area, the bounced output WILL be the same. The problem is that not all units are 100% efficient across the flood/spot range, and don't always give you a linear increase in output when spotted in.

So that should anwer your second question: as long as the original pool of light is within the boundaries of the bounceboard, you generally get the same amount of light bounced back whether the unit is close or far from the bounce. But once you pull the light far enough back that the pool spills off the edges of the bounce, you're starting to "throw away" that light and your bounce level starts to drop.
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