On Tue, Jul 23, 2013 at 12:29 AM, Aahz Maruch <[email protected]> wrote: > On Thu, Jul 11, 2013, Bruce Walker wrote: >> >> http://flic.kr/p/f7BHhH Dogwood berries >> >> Tried my new 30" octa umbrella softbox for macro work; I like it. >> Reversed the flash to increase specularity and create more of a >> spotlight effect. > > What do you mean by "reverse the flash"? (Tried quacking but got mostly > comic book hits. ;-)
[This is where plain-text breaks down for communicating visuals. I'll try ... ] Usually one expects the light from a softbox diffuser to be even all across the surface. That is, if you metered the light in the center, sides and corners you'd expect the same reading. Plus, the light is generally diffused twice before it reaches your subject (there's an inner diffuser) so it's super soft, spreading light; directionless within the area of the front diffuser. With an umbrella softbox you achieve that by installing your flash near the front diffuser, but pointing inward toward the silvered insides of the umbrella's central spine. So the light bounces all around inside and exits through the diffuser (white scrim) nice and soft and even, doubly diffused. For a different look you can "reverse the flash" by setting it near the umbrella spine, pointing toward the diffuser. Now most of the light will be concentrated near the center of the diffuser with fall-off toward the edges and corners. If you meter the surface the center will be 2-3 stops brighter than the edges. In addition, there will be some hard specular (directional) light because you no longer have a double diffusion effect. This actually resembles the look from a beauty dish, which is a neat hack because those suckers are very pricey objects (apparently made from rare elements or something). HTH! -- -bmw -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
