Flash is definitely set wireless slave mode. There is one for P-TTL and one for just manual mode. I tried them both with exactly the same results.

Been reading the forum for a while but this is my first post.

Hi Everyone,

I have a question. I got K20D and Sigma EF500 super flashgun which I was using with my K100D off-camera by attaching them with 2 hotshoes and cable. K20D works the same way.

Now that I got K20D though I want to use the commander mode of onboard flash to trigger sigma EF500 super off-camera wirelessly. According to sigma manual this is possible.

1. I set flash to C0 SL ( channel 1 slave mode) with wireless symbol.
2. Turn off Flash and place it on camera.
3. Turn both camera and flash on. press shutter half way
4. Turn off Flash and Camera, Take flash off the camera. Turn them on.
5. Pop onboard flash up (it is already in commander mode and set to wireless mode)
6. Take a shot at 1/125 at any aperture. Flash at full power.

The result is the same whatever happens. I get black photo (cap is off). I can see onboard flash is firing and triggering the sigma in slave mode but light doesn't register on the photo. I tried slower shutter speeds and still nothing. ( batteries are fully charged)

I remember there was some talk some time back that to do this flash in wireless mode it needs to be rechipped by Sigma, whatever that means.

Any advice would be welcome. I would love to have got Pentax 540 model but it's a bit out of my budget at the moment.

Thanks in advance

Dan