Originally posted by ChopperCharles No, you cannot. The Vivitar 550FD does not work on a K-x. The shutter speed setting goes haywire once the flash is attached and turned on, and it will fire intermittently if at all.
Charles.
This is not true. If you use the 550 FD M/P/O (Minolta, Pentax, Olympus-- it'll say on the top right corner of the back) keep it on A1, A2, or M. It will work perfectly using the onboard auto mode, as well as manual full power.
If you put it on TTL it'll freak out, as Pentax DSLRs haven't supported TTL since the *ist's.
I have used my 550FD N (Nikon) on my K100d and my girlfriend's K-X without issues. I passed it off to a friend with a K10d and he loves it. It was the best $1.75 I spent at a thrift store before upgrading to a pair of 285HV's.
I have also tested the C/R model (Canon, Ricoh) and it worked fine, too. I've never tried the M/P/O model (Minolta, Pentax, Olympus), so maybe even in manual and onboard auto the contacts confuse Pentax DSLRs? No need to buy the Pentax model, though, as you won't get TTL-- I think the C/R model is the cheapest.
I tested mine, and the trigger voltage was around 11v, but I didn't have a super accurate volt meter. These things work great, and if you don't need a ton of power and manual control, you can pick them up for $10 or so. I learned basic flash techniques, and once you start bouncing, you'll get hooked and want to become a flash master.