Hi Jostein, This may have something to do with my P-TTL problems and my macro set up, given that I am running 2 flashes at a distance of 5 to 10 cm. Though I'm metering the preflash with the aperture closed to f16 on a 38 mm or 20mm lens with up to 25cm of extension, so it's unlikely that the preflash is overloading the camera.
Still it's more information for the puzzle. Thanks for the info. Leon On 29 April 2011 21:57, AlunFoto <alunf...@gmail.com> wrote: > In the AF-540FGZ manual it says there is an absolute minimum usable > distance in P-TTL (0.7 m). I always thought that was because the flash > was unable to quench its output fast enough to operate at shorter > distances. I thought so because quenching the blink was how the old > TTL system worked. Then, today I took the flash off-camera and began > experimenting. To my surprise, the shots where the flash was closer > than 70 cm from the subject became underexposed, not overexposed. It > got worse the closer I held the flash. > > The only explanation I have come up with is that the power used for > preflash must be constant, and too strong to let the camera meter > accurately at distances shorter than 70 cm. > > Maybe this was obvious to everyone but me. So, eureka or d'oh? > > Jostein -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
