Frantisek Vlcek wrote: > > t> Basically the calculation is the same, the difference is that the > t> distance is from flash to bounce point to subject. The X factor is how > t> high the ceiling is, so I don't think there's any rule we can give you. > > Is that true? The normal calculations works for spread of radiation, > according to the square root rule (right in English?). Spread from > point source. But bounce flash is so nice because it isn't a point > source. Once it hits the ceiling, it radiates like from a plane > source, for which the formula doesn't work (it doesn't diminish with > the square root of distance). That's why bounced flash looks so > natural, too.
I was under the impression the rays just bounced off the plane at the angle they came in at (angle of incidence?). The bounce doesn't spread them out any more, though I guess a stucco style ceiling might do a little of that. The light *is* more spread out because it's traveling farther. I don't think the results look nicer because of the diffusion, they look nicer because of the angle. They still look like point source lighting shots, it's just that the point is effectively shifted somewhere over their heads. In any event, the calculation works in practice. tv - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
