Excerpt: Haven't had a great need for a flash unit, the on-camera flash has been sufficient. But I'm finding that the subjects I'm currently shooting require something more versatile with greater output. The AF-540 fills the requirements. Can be hot shoe mounted or positioned off-camera using it's included base or on a light stand. Wired or wireless, as needed.
Excerpt: My experience with flashes is as follows : Pentax AF280T, Vivitar 285HV, Pentax AF500FTZ, Yongnuo 460, Yongnuo 560, Sigma 530 ST DG and now the Pentax AF-540FGZ. I've tried a bit of everything.
Pros: Powerful, offers just about every control possible
Excerpt: A good powerfull flash, which matches the Pentax bodies brilliantly. For easy photography it works very good: TTL techniques makes sure you get a well-lit image. Tilt and swivel head makes it possible to to use the reflective walls/ceiling and more depth in the image. That was the reason to buy a 540 (and not 360 instead, although I did not need the enourmous power of the 540).
Excerpt: This is my only flash so it gets used for about everything. It needs more power and control of the head, it turns on it's own and you find the flash head facing the floor. The cordless system needs some rethinking, if you turn off the camera to change cards you have to reprogram the flash and camera. That's ok for flowers but not so good at weddings atleast not for my style. I like the flash overall, the light is beautiful.
Pros: Consistent Output, Fast Recycling, Lightweight, Versatile
Cons: Bulky, Needs more power, The Tilt Lock is Weak