Originally posted by MPrince It will work just fine in x-sync mode and aperture priority mode. All you have to do is make sure the aperture and ISO settings on the flash match the camera settings.
That is a very loose definition of just fine
Flash automation on Pentax really fits into 5 categories
1 Full P-ttl inc wireless (very flexible for multi flash shooting)
2 partial P-ttl some cheap off brands and low spec units features missing usuall wireless , master etc (limited multi flash use)
3 Pentax fit Auto flashes , these range from metz sca 372 through to Pentax 500 these flashes will set x-synx, aperture and iso from the flash to the body (easy multi flash but not flexible)
4 Sinlge pin 'Auto' inc other manafacturers fit flashes, no automation but will allow correct exposure providing body as manualy 'set' to match flash (easy multi flash but not flexible)
5 Manual flashes here you control everything and is not really any mor complex than 4 above once your comfortable with your flahses your'll generally get it right first time everytime for simple flash solutions (very flecible for multi flash shooting)
For serious flash shooting 1 and 5 are you best bets, but you can mix 3,4 and 5 to give a set base level with fine tuning from the manual flashes.
Choices should be made based on 'system' setup which will normally revolve round triggering.