Pentax *ist D & Wireless flash problems

nicolphoto · Jul 2, 2004

Having trouble with a Pentax *ist D (in wireless flash mode, on board flash popped up - used as a controller only) trying to trigger 2 - AF360FGZ wireless flashes (set as slaves - in the P-TTL mode) into white umbrellas.

Settings have been triple checked - and flashes will fire (wireless) when they are pointing directly at subjects. When they are pointing into the umbrellas (sensor is away from subjects) it seems that there is not enough light reflecting off of the umbrellas, from the control flash, to get them to fire. I was under the impression that the flashes would work with wireless communication and not by "optical" means. Called Pentax and they will look into the problem - not holding my breath for a response.

If someone has had experience with this flash and the *ist D and could help me out I would appreciate it.

Bruce N.

photobug · Jul 2, 2004

Bruce, have you tried shooting through your umbrella? If that doesn't you might have to use a soft box instead of the umbrellas.

Sorry I couldn't be more help.

nicolphoto · Jul 3, 2004

Thanks.

I actually found someone with half a brain at the Pentax HQ. They told me that I need to place a "bounce" near the sensor so that light could be directed into it.

Thanks for the suggestion - I was thinking about that too.

Bruce N.

tr0gd0o0r · Jul 4, 2004

Thats a pretty interesting solution to the problem. But am I understanding you right. The way the wireless flash is triggered by the *istD is by the light of the internal flash bouncing back? (Guess that explains why i could never get the wirless to work without the internal firing)

nicolphoto · Jul 5, 2004

That is what I was led to believe.

Talking to a Pentax Tech, he said that the wireless part of the camera is done using the flash - not radio frequency or other means. The on board flash (RTF) sends out a bunch of pulses, how hot to flash - what channel the camera is using - and other info, into the little round sensor near the infra-red autofocus assist. If it does not reach it, then it doesn't go off. Therefore if the subjects are too far from the flash, or theres too many bounces to get back to the sensor, the flashes will not go off. With a little bit of ingenuity and some duct tape anything is possible.

Happy flashing.