Originally posted by StarDust If you want to buy a 3rd party flash, does it have to be Pentax specific like a Tamron lens has a K-mount or does any (Metz 48 AF-1) flash work?
I'm going to add some stuff covering this to the flash guide. As you've figured out, the flash systems are specific — if you look at B&H or somewhere, you'll see Metz 48 AF-1 for Pentax, for Nikon, for Canon, etc. Same with Sigma. Some other Metz flashes are different, though — they have a generic flash unit which has swappable modules which are camera-specific. (Might be nice if you have multiple brands of cameras.)
Pentax doesn't license their flash protocol, so all of the third-party compatible flashes are reverse-engineered. This works pretty well, although occasionally there are problems. That's why Metz has the USB port — if the K-7 turns out to act differently, they can release a firmware end-users can upgrade. With Sigma, you can send the flash back to the service center to be upgraded (for free). With Sakar/Tumax et al you're probably out o' luck.