[RSO]

The YN 560 is usable as a manual, optically fired, flash with a Pentax camera and a controller flash. The model that I have does not have it's own radio wireless capability and I don't think that the Metz 50 Af-1 flash has radio wireless capability either.

I have tried to use the same setup, as described above, on both the Pentax K-5 with the built in flash as controller, and now with the K-1 using a dedicated Pentax flash as the controller and the Metz flash acted the same using both camera's. Either slave flash will work in the expected mode, and the YN 560 will always fire, but the Metz flash will not fire in p-ttl mode with the YN 560 in the setup.

I don't understand why it won't work, but I have attempted to make the mixed manual flash p-ttl system work using only optical triggers several times. As I stated in the original post I expected that the YN560 would just fire in manual mode and the p-ttl flashes would attempt to set exposure.

As an aside it is possible to use the Metz in p-ttl mode with a control flash and fire the YN 560 in manual mode, but I had to resort to setting up optical wireless p-ttl and then firing the YN 560 using a radio transmitter connected to the camera pc port. This setup works as expected and flash compensation can be used to get a good exposure.

If anyone has the same setup I would appreciate confirmation that I'm not crazy!!

[Quartermaster James]

Okay. Sorry for the red herring.

[West Penn]

Can you orient the Metz and YN flashes so that the optical receiver on the YN can only see the flash coming from the Metz and not what the PK flash is doing? In other words, you want the YN to get it's firing signal from the Metz and not the PK. This orientation of the flashes may not be practical for shooting the photos you want, but it might explain why you're experiencing the failure of the Metz to fire.

[nono]

Just what I was going to suggest. The only explanation I can think of is that the p-TTL pre-flash triggers the Yongnuo optical slave, which drowns the controller light so the Metz does not see the full p-TTL sequence (I assume it is a sequence, not just a single flash).

[grahame]

I didn't read all the replies, so it might have been bought up for discussion:
p-TTL flashes pre-fires first and get the read of reflection light from the pre-flash to calculate the output power. Some flashes, when set a slave model, allow for ignoring the first pre-flash and fire with the 2nd real flash from the controller /master flash. If that flash can not do that, or wasn't set that way, the controller might get way more than expected light back (from the slave flash) and think it is not necessary to fire the flash.
I believe Yongnuo can be set to ignore the 1st flash. But you will have to read the manual.

[mcgregni]

It does sound feasible that the pre--flashes might be firing the Yongnuo too early and then the bright light from the Yongnuo is overpowering the triggering signal pre-flash and so the Metz slave is not firing.

Really, it probably is the case that the Yongnuo optical modes are not.able to work with the complex pre-flash sequences of the wireless P-TTL system.If the flash has a delay setting you might be able to figure out the correct timing for the main flash .....when I use this approach, with a P-TTL controller flash, I use 100ms.

[grahame]

It is a lot easier to set flashes in manual model than using p-ttl model in such complex set up (combination of different flashes). Since you have to set several flashes, I guess you have some time to test light condition before real work starts. Set them at M and try a few shots and you will get much more reliable setting.

[RSO]

"It does sound feasible that the pre--flashes might be firing the Yongnuo too early and then the bright light from the Yongnuo is overpowering the triggering signal pre-flash and so the Metz slave is not firing."

I found this comment to be intriguing and so I conducted the following test.

I used the same set up. Pentax 360 as the controller. Metz 50 af-1 in slave mode and the YN 560 also set to slave in the proper mode (mode 2 which ignores the pre flash).

This time I set up the YN 560 so that I could put a stack of paper on the top of the flash to block the flash output.

The Metz flash functioned normally in p-ttl mode. So it must be the light from the YN 560 interfering with the Metz operation.

I don't understand why as the pre flashed should be prior to the Metz firing.

Someone mentioned just setting up in manual, which I did with the K-5 and it worked well and didn't take a lot of time. P-ttl flash worked intermittently on the K-5 so you didn't have options.
I have found p-ttl flash to be very useful when you are shooting outdoor portraits the last hour of the day (magic hour). The ease of changing locations versus all manual flash has allowed for more shots in the limited period of good light, which is why I have pursed the blended manual p-ttl option.

[mcgregni]

I think the most reliable way to sync the triggering of a wireless P-TTL flash plus a manual one is to use radio triggering for the manual flash. You would need a trigger that has a 'TTL Pass-through' feature with a hotshoe on top for your controller flash..

Otherwise then 'dumb optical' triggering will always be a bit experimental, as the number of pre -flashes varies. Your Yongnuo flash doesn't know that it is being controlled by wireless optical signals, it will just fire as soon as it detects a strong enough light. See if it has a special SL2 mode for ignoring pre-flashes, or if that doesn't work then try a delay setting of 100ms, assuming your flash has such a thing.

The delay is longer when using wireless P-TTL than a single on camera flash, because there are more pre-flashes for wireless operations.