Sigma EF-500 , used wirelessly, why Less power?

[TBAM]

I recently tried using my Olympus' wireles RC mode with my Sigma flash (Pentax mount).

It worked, but for some reason the power dropped dramatically. To the point where it was useless as an off-camera flash.

The camera is in RC wireless mode, and the flash is on slave mode. The flash says it is on full power (1/1), but there's just not enough light to even constitute fill flash.

When I put the flash back on the camera, the power goes back to normal.

I understand there may be complications with using a non Olympus flash unit wirelessly with an Olympus camera. But even if the wireless is just used as a trigger, it should provide better results than this.

I'm talking 4-5 stops difference in exposure atleast between the light when the flash is off-camera to when it is on camera.

Is there something I'm missing? I've read both the Sigma and Olympus manuals to no avail.

Any help would be greatly appreciated.

 

[Steph]

Well, first of all, the flash will not work in RC mode. You need a dedicated flash such as the Olympus FL-36R or FL-50R to wirelessly control the flash from the camera. If you can use the Sigma as a slave (not all flashes can be used as slaves), you will have to set the power manually (on the flash) and use your built in flash as the master.

 

[frXnz kafka]

Are you sure it's exposing your photos at all? I assume you're triggering it with the pop-up flash on your camera. My guess is the pop-up's pre-flash is triggering the Sigma prematurely, and so it's not adding anything to the exposure.

 

[Big Mike]

Are you sure it's exposing your photos at all? I assume you're triggering it with the pop-up flash on your camera. My guess is the pop-up's pre-flash is triggering the Sigma prematurely, and so it's not adding anything to the exposure.

That would be my guess as well. It's probably using an optical trigger (it fires when it sees another flash) but the flash you are using to trigger it (the built in flash?) probably fires a pre-flash for metering. The preflash triggers the remote and it can't fire again for the actual exposure.

 

[frXnz kafka]

it can't fire again for the actual exposure.

Or it's possible that it is firing a second time, and just dumping what little charge it has built back up (if any).

 

[Big Mike]

That's possible, but the point is that it can't fire as it should, which is just as bad as not firing.

Some optical triggers have the option to ignore a pre-flash. I wonder if this unit has that?

 

[TBAM]

That would make sense if it was flashing prior to taking the photo.

I assumed they still communicated correctly as the Sigma flash did not work if the channels did not match (the Sigma flash allows selection of channels).

I haven't yet purchased an Olympus flash unit as the Sigma is quite powerful and versatile and it's not worth spending $400 AUD just to get ETTL on a lesser powered flash.

Would assigning the flash to rear-curtain lessen the chance of the flash firing prior to the exposure, or would the shutter-speed still be too fast for the majority of shots?

I think it is the mis-firing of the flash, as I have set the flash manually to full power, and it is still as though there is no flash.

When I get home, i'll try turning the RC mode off, and just uising the built in flash normally to see if the Sigma fires on the flash of the camera alone.

I've heard of third-party flashes still working wirelessly with the only communication being the trigger, but I didn't even think about the possibility the flash might be firing off the pre-flash communication normally intended for Olympus made compatible flash units.

 

[Big Mike]

I don't know much about Olympus...can the camera itself (or the built-in flash)...act as a master in it's wireless system?

With Canon, for example...I think you could use a Sigma flash in it's wireless system...but you would still need a 'Master' unit on the camera to control the 'slave' unit.

 

[TBAM]

The Olympus can apparently control up to 3 groups of flashes. It does this through optical communication by the on-camera flash (through a series of flashes prior to the photo being taken).

So yeah, the E-420 can act as a master. It has a number of functions in the RC (wireless) menu in regards to TTL and channel selection, rear curtain etc etc.

I thought that wireless was wireless. I read that at the very least, the Olympus system could wirelessly transmit a trigger system for a 3rd party flash.

I assumed the Sigma was communicating correctly with the Olympus when I changed the channel on the flash.

The flash has channels 0, 1, 2 and 3 wheras the olympus has 1, 2 and 3.

When the camera was on channel 1, and the flash on 1 it would not fire. When I changed the flash to channel 0, it worked.

The Sigma's wireless receiver was flashing, which I thought was meaning correct communication between the devices.

However, it does seem as though the off-camera flash is firing before the camera is exposing. How to remedy that will depend on if the Sigma flash works just off the normal Camera flash firing alone, or if it requires the RC (wireless) communication flash as well.