Originally posted by DonV I don't know and do not see any definition of "controlling" - what does this mean?
For "F" flashes it means both the flash and the camera have the "digital" contact that allows a "conversation" and exchange of complex information for digital protocol TTL and/or P-TTL and associated features. For non-F flashes the choice of wording used by the page authors is poor. For analog TTL, the body is able to "quench" the flash when sufficient light has reached the film. That is the full extent of control and only applies to those bodies that
use the analog TTL protocol exclusively (Super Program/Super A, LX, and 645...IIRC) support the analog TTL protocol when paired with those flash.* For analog dedication using the "center", "mode", and "ready" contacts, the flash provides information to the camera, but not the other way around.
As for your AF400 FTZ, it supports TTL and manual modes only using the digital protocols and is of limited usefulness on a Pentax dSLR. You can download the manual for free from:
Pentax Manuals | Accessories (PDF password = Pentax)
Steve
* Those flash and bodies that provide broad support usually have a compatibility matrix in the user manual.