My onboard flash is doing something weird...

[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(Pentax k10D) 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?

[OmahaAdam]

What sort of strobes do you have? It would be worthwhile to invest in a sync cord.

[gahspidy]

The only thing that I can think of here is that your on board flash is firing a preflash (occurs a millisecond before the actual flash) and your strobes are tripping on that. so they may just be firing slightly ahead of time because of that. Most decent optical strobes have a setting for preflash triggering so that it waits until the second flash to fire. Maybe the setting on your optical strobes changed. Or the other way around. Maybe the strobes are set for preflash and your on board is not firing a preflash, in which case maybe you changed the setting on the camera to a manual flash output or something where no preflash is used. One way or the other, I think the issue is with the preflash setting.

[MJS]

Do you have Red eye correction accidently set on your on board flash?

[Dylan8i]

could also check to make sure the flash is front curtain and not back curtain (i believe thats the term- im kinda tired).