For some reason the operating manual for AF360/540 is covering only P-TTL wireless mode as if wireless mode can not be used with A or M modes. But the good news is: wireless option is NOT restricted to P-TTL! K10D/K20D's on-board flash in wireless flash mode can control AF360/540 in P-TTL, A and M modes.

Great! Now, how to use it? Here are the steps:

1. Make sure the flash is in SLAVE 1 mode, and set to "Wireless" and "Slave".
2. Mount any lens with aperture control, A or newer. (For the reasons of not interfering with P-TTL mode if K and M lenses are mounted wireless flash option is disabled in the "Fn" menu.)
3. Make sure both the body and the flash(es) are set to the same channel. The body will briefly display channel on the top LCD once you exit the "Fn" menu with wireless flash set.
4. For full control set the body to X or M mode. If shooting with manually adjusted flash output or studio strobes, exposure is controlled by APERTURE ONLY (you can add available light using slower shutter speeds, but that won't affect flash at all). DO NOT let camera decide anything for you. Remember, the goal is to be in total control over all parameters.
5. Suggestion: If you shoot any polished/reflective objects set on-board flash to "controller" mode, that is, not to fire main flash with remote flashes. (Custom Menu -> Flash in Wireless Mode -> Off) For fill flash set it to "On", but better get another AF360/540 and fire it as a fill light in 1:4 or 1:2 power ratio to the main flash. (Note: On-board flash in controller mode will still fire, but at lowest power. So it's not really "off", but for all practical purposes it looks like it does not fire.)

As already mentioned, this will work with the flash set to P-TTL, A and M modes. P-TTL is covered in the operating manual, and I don't see any point in using the "A" mode in wireless, so here is how it works in "M" mode: If AF360/540 are set to M mode the whole communication sequence will be executed in the same way as with P-TTL sequence. AF360/540 will be aware that a Pentax body is "talking" to them and respond properly. No other flashes from other cameras will set them off (like in SLAVE 2 mode). Finally, AF360/540 set to M mode will simply ignore relayed P-TTL power adjustment and fire at manually preset intensity. Sweet! Like with studio strobes!

Here is the example of two AF360 units (with shoot-through umbrellas) controlled by K10D. Tests were done in both "master" and "controller" mode. If K10D is in the "master" mode you can see the reflection of the on-board flash. In the "controller" mode there is no reflection and the image is slightly darker as expected (less light):



This is with AF360 set at full power. Why is that important? Well, since AF360 recycle time is about 5 seconds there is no way AF360 can fire mistakenly on P-TTL preflash and recover fast enough to fire again with the main on-board flash. So it really works as expected in SLAVE 1 mode.

I have also tried shooting in the studio with one AF360 with on-board as controller, and it works!!! Next time I'll try two AF360s, but here is the result with only one AF360, shoot-through umbrella, K10D and DA 16-45, no adjustments or Photoshop work:



Models: Ashley Pimentel and Lise Maher
Makeup: Leslie Gray
Photographs by: yours truly :-)

P.S. This is the answer to my own question posted here:
https://www.pentaxforums.com/forums/458178-post1.html

[Adam]

Article approved. Thanks for the great submission!