Originally posted by hoanpham Flash unit does have limited power. If you want to dim sunlight in the background, you may need more than one flash unit. Then you need to deal with Pentax's weird 1/180 synch speed. May be it's a nice-to-have feature, but no real need.
I need full control flash/light setting here, cannot depends on this feature in the camera. It's better to use ND filter(s) in combo with several flashes. Better with higher flash sync speed and lower iso than 80 (ie 25, 50 or lower)
I was not talking about having a more powerful on-board flash for Fill-in here, I was talking purely about the sync burst used in wireless controller mode.
In this mode, the on-board flash should not participate to the exposure (as is the case with other cameras such as the K20, or Kx), but with K7 & K5, Pentax upped this sync burst power, so much that it became visible when used in low-light, ambient-balancing situations.
I guess they did this to allow a better sync in full sun, but it's a real pain for indoor shots. You have to screen the on-board flash so it doesn't ruin the picture.