John, You describe how I would expect the flash to function. My observation was that at _one_ particular zoom setting, 48mm, the output is two stops brighter than any other zoom setting. This also includes 58mm which, as you say, should produce a more concentrated beam. If there was any logic to this the 58mm zoom setting should have been even worse than 48mm, but the histogram at 58mm is perfect... :-(
Jostein 2009/7/10 John Francis <[email protected]>: > The flash doesn't have more power output when zoomed, but it does > concentrate the flash output in a smaller field of illumination. > This means that an object will receive more illumination when the > flash is zoomed in. If you're getting close to being within the > minimum distance, you may well find that the flash cannot quench > fast enough to avoid blowing out the exposure. > > Notice that the Guide Number for the flash depends on the zoom > setting - from the table on p82 of the manual you can see that > the guide number varies significantly as the head is zoomed. > > > -- > 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. > -- http://www.alunfoto.no/galleri/ http://alunfoto.blogspot.com -- 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.
