[r.hagell]

I have both the K5 and the DF-383-PEN (purchased from B&H) and both work fine except I can't get the flash to work in the wireless slave mode. The boxlet that came from Vivitar and the on-line reviews all say that it just works but I can't get it to. It see the master flash on the camera and fires but out of sync no matter what shutter speed settings I try. ????

[elliott]

I'm looking at the manual for that flash, it has an optical slave mode, but I'm not seeing anything to get it to ignore the pre-flash of the P-TTL system. It is a dumb slave, it doesn't do wireless P-TTL, it just flashes when it sees another flash and you set the power manually.

If you can't set the optical trigger to ignore the pre-flash you are going to have to find a work around. I use radio triggers for off camera flash, I have the Yongnuo RF-602, but I wouldn't recommend them because they require modification to work properly on Pentax. The cheap PT-04 triggers found under many names will work fine with Pentax out of the box, along with the more expensive Cactus triggers. I've heard the Yongnuo RF-603 isn't Pentax friendly either.

Alternatively, the Yongnuo YN-560 version 1 flash has an optical slave mode that will ignore pre-flash. It can be found on Amazon for $46 and it is meant to be used off camera in manual mode. It has power settings from 1/1 to 1/128 with plenty of adjustment in between, unlike the Vivitar's 1/1 to 1/16 manual power settings. That way you can keep the Vivitar for on camera P-TTL work and have the Yongnuo for off camera work and even use them together, you can never have too many lights.

[r.hagell]

So if I have you right. It is just a dumb slave - OK, but then it also can't ignore the pre-flash. So as a wireless slave it's useless with this camera and will always not be able to sync with the shutter.

You are recommending another flash, Yongnuo YN-560, that may work with the K5. I wonder if anyone has actually used this combination successfully. Yes, I hear what you are saying but I'd like to check because I bought this unit having been told that it does everything just fine. This Vivitar is a good unit on camera and I can see the advantage of a separate unit off camera, it's not that. I just want to know that it will work as you say it is will with the K5. It seems the 383 works with other Pentax camera.

$46 is a an excellent price to solve this - what do these radio triggers cost?

Oh and thanks much!

[elliott]

So if I have you right. It is just a dumb slave - OK, but then it also can't ignore the pre-flash. So as a wireless slave it's useless with this camera and will always not be able to sync with the shutter.

I'm not sure why they would leave out the option to ignore pre-flash, even some really basic slaves have it. I guess they figure you would be triggering it from a manual flash, which has no pre-flash. You could force your onboard flash to not do a pre-flash if you use a lens that doesn't support automatic aperture control, but it would fire at full power and might add unwanted light.

You are recommending another flash, Yongnuo YN-560, that may work with the K5. I wonder if anyone has actually used this combination successfully. Yes, I hear what you are saying but I'd like to check because I bought this unit having been told that it does everything just fine. This Vivitar is a good unit on camera and I can see the advantage of a separate unit off camera, it's not that. I just want to know that it will work as you say it is will with the K5. It seems the 383 works with other Pentax camera.

It seems the Vivitar does everything it says it will on the K5, it just has limitations that a Pentax or other more expensive flash doesn't. I believe Metz and Sigma both offer flashes that will do P-TTL wirelessly, but they are more expensive than the Vivitar. The K100D does the same pre-flash as a K5 and I have reliably triggered my YN-560 with it. If it is being triggered by a P-TTL flash with the pre-flash you would use S2 mode, without the pre-flash is S1 mode. It is a really simple flash to use, everything is manual though, so there is a learning curve. I've had mine over a year now and the only time it gives me problems is when the batteries get really low.

$46 is a an excellent price to solve this - what do these radio triggers cost?

Radio triggers can be as cheap as $20 for a transmitter and receiver pair with the PT-04 models, Cactus V4 triggers are about double that. I haven't used either of those, but I hear good things about them. They will offer more flexibility than just optically triggering the slaves, since you don't need line of sight and you won't be using an on camera flash that could add unwanted light. They also eliminate the possibility of someone else nearby setting off your slaves, which can ruin their shots and yours. If you want to get serious with off camera flash radio triggers will definitely be worth it. Keep in mind they will not pass P-TTL, so the slaves will still be controlled manually, but controlling them manually is more predictable than P-TTL with off camera flash.

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Last edited by elliott; 11-20-2012 at 12:05 AM.