What is my onboard flash doing??

[Dubious Drewski]

I've done this a thousand times, but now something's changed and I can't make it work. I normally use my onboard flash as the controller for my strobes(It's all 100% optical, no radio). It's supposed to fire, trigger all the slave flashes and not show up in the photo. But something's not working....

Any ideas guys?

 

[Garbz]

Not sure specifically what you are doing but I can tell you what's happening.

Either:
a) Your onboard flash is TTL preflashing, and the strobes are triggered during the preflash and miss the shutter by firing too early.
b) Your onboard flash is not TTL preflashing, and your strobes expect it to and are triggering too late.

Sorry that's the theory, as to why you'd need a Pentax man/woman to explain that.

 

[asfixiate]

Can you put the autofocus on servo instead of AI focus. Also wouldn't turning off red eye filter help?

 

[JerryPH]

Set the built-in flash NOT as commander, but to MANUAL and lower it to something like 1/128th.

 

[Dubious Drewski]

The onboard flash cannot be fired manually. But what's crazy is that I USED to be able to shoot this way and it suddenly stopped. Something's changed, but I can't figure out what.