Russ: The way I read the manual, the ISO of 100 is not supported in iTTL mode. The comment of using 3200 and greater is meant to be a warning that the iTTL function may not be able to adjust the flash exposure enough for certain apertures and distances. For example, F/2.8 and 2 feet distance comes to mind. At that distance and aperture, the correct flash duration will be shorter for the correct exposure than the iTTL computer can handle. Hope this helps. James -----Original Message----- From: owner-photoforum@xxxxxxxxxxxxxxxxxx [mailto:owner-photoforum@xxxxxxxxxxxxxxxxxx] On Behalf Of Russ Sent: Wednesday, August 03, 2011 6:08 PM To: List for Photo/Imaging Educators - Professionals - Students Subject: Nikon D90 and flash Hi Gang................ After the theft of my camera equipment a few weeks ago I purchased a refurbished Nikon D90 a Tamron 18-200mm lens and a Sunpak pz42x flash. (fortunately the thieves didn't touch any of my Studio equipment) I have looked on some of the Nikon forums and don't see anywhere where this question has come up.............. On page 237 of the Users Manual it states............ iTTL flash control can be uses at ISO's between 200-3200 It mentions that desires results may not be as expected when using 3200. The Nikon D90 can also be set at ISO 100 and 6400. Does this mean that the iTTL flash control will not work if I lower the ISO sensitivity to ISO 100? That seems rather strange? Thanks Russ
