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 -- http://www.alunfoto.no/galleri/ http://alunfoto.blogspot.com -- 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.
