Jostein, I just ran a series theu the K-7 and 77 Ltd at F8 with the 540 Flash. My flash doesn't show any anomalies when zoomed to 48mm vs 16, 24, 34, or 58. Exposure stays the same. I think you have a flash fault. Regards, Bob S.
On Sun, Jul 12, 2009 at 4:03 AM, AlunFoto<[email protected]> wrote: > Could I bother you guys to take a look at this comparison: > http://www.alunfoto.no/temp/flashAnomaly/flashtest.html > > All shots obtained at a working distance of 2 meters, and with > constant ambient light. The 48mm series stands quite distinctly apart. > > Graydon and John (or others), if you still think this is rationally > explainable by other factors than a faulty flash, please let me know. > > Jostein > > 2009/7/11 Graydon <[email protected]>: >> On Fri, Jul 10, 2009 at 10:10:23PM +0200, AlunFoto scripsit: >>> 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... :-( >> >> If there's a step function in the output of the flash, though, and "over >> 48" gets stepped down and _up to_ 48 does not get stepped down, it's >> quite possible that 48 would result in blown highlights while 58 >> wouldn't. >> >> Why this is happening goes back to the usual "evil algorithm vs hardware >> fault" question. >> >> -- Graydon >> >> -- >> 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. > -- 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.
