Optical slave triggering of Canon flash in a studio set up

[HoppyUK]

In this thread http://www.talkphotography.co.uk/forums/showthread.php?t=159420 the OP asked if you could use a simple optical slave to trigger a Canon hot shoe gun in a studio lighting set up. I said you could, and I bought one to do just that with my 580EX. It works, but will only fire the flash once; you then have to turn the flash off to reset the slave before it will fire again, just once - obviously useless :bang: The OP had the same problem.

I couldn't understand why, but after a few hours googling, I have found the answer, which is a slightly modified optical slave which gets over a condition which I believe is common with a lot of hot shoe flashes - the SCR lock-out (silicon controlled rectifier).

Apparently there is residual current present in the gun's hot shoe which prevents an optical slave from resetting itself, but some simple electronic components in the cable can sort it. This guy, Michael Bass in the US, sells the bits you need - the trick cable is $40 and if you want a hot shoe that's another $40, optical slave $20 more. http://michaelbass.blogspot.com/2007/01/misc-custom-connections.html#CanonSoniaConnect

Michael Bass also custom makes dozens of different leads and connectors to get around the myriad of problems associated with stobist techniques, especially when trying to make dedicated auto exposure guns work in ways they were not primarily designed to. He's also extremely helpful as well as knowledgeable - answered my emails in a few hours

Here's a link to another handy site with simple instructions to fit a sync socket to a Canon 580EX http://blog.rrdphoto.com/2007/04/how-to-add-sync-port-to-canon-580ex.html But if you want to plug an optical slave into that, which seems to me to be the best way of getting hot-shoe and studio flashes to sync up together, then you'll still need Michael Bass' magic connector

 

[david1701]

now that I never new, thanks hoppy for a v informative post, I'm gonna grab an optical slave for some cheapo manual flashes and I'll experiment with it on my 430

want my proper triggers now

 

[classcams]

Read this thread with interest. Indeed the Canon flash guns (430 ex) will only fire one flash. All the old style flashguns are ok. Have to look into this a bit deeper. By the way, my Metz flashguns 48 AF-1, very similar to Canon, fire as many as you like. Why use a Canon when any old gun can be used as a slave providing it is power adjustabe.

 

[PerfectSpeed]

Hey HopyUK

I've dealt with Michael Bass before and agree, top guy, super fast shipping too.

 

[HoppyUK]

Read this thread with interest. Indeed the Canon flash guns (430 ex) will only fire one flash. All the old style flashguns are ok. Have to look into this a bit deeper. By the way, my Metz flashguns 48 AF-1, very similar to Canon, fire as many as you like. Why use a Canon when any old gun can be used as a slave providing it is power adjustabe.

Metz have always made very good falsh guns and I'm sure the 48 AF-1 is no exception - it doesn't seem to be much cheaper than Canon though.

It would be interesting to confirm if you have actually used this Metz flash with an optical slave, and that it does indeed fire repeatedly with one?

Cheers.

 

[mick johnson]

Thank's Hoppy, for saving me a fiver.. I tried my ST-E2 today with the 4 pins taped. It fires the studio lights ok but fails with the 430ex (manual)

The 430ex actually fires but not at the right time.

I also tried my 550ex with ETTL turned off, but same result.

 

[classcams]

Metz have always made very good falsh guns and I'm sure the 48 AF-1 is no exception - it doesn't seem to be much cheaper than Canon though.

It would be interesting to confirm if you have actually used this Metz flash with an optical slave, and that it does indeed fire repeatedly with one?

Cheers.

I have bought twne last week,but with the falling pound 189 quid. Both guns on ETTL, fire one manually, second one fires. Fired them 3 times.

 

[Dogfish_magnet]

I've had the same issue with a 550ex and a PC sync cable, being fired by timer i built, this had worked fine with a Nikon SB600 but the canon need to be reset after each shot, i had to change the value of a resistor on the timer to get the flash to work correctly .

 

[HoppyUK]

Thank's Hoppy, for saving me a fiver.. I tried my ST-E2 today with the 4 pins taped. It fires the studio lights ok but fails with the 430ex (manual)

The 430ex actually fires but not at the right time.

I also tried my 550ex with ETTL turned off, but same result.

Only a fiver! Mine cost £11 from Jessops, and the identical Kaiser from Warehouse Express is £18

Looks like we've both been doing the same tests, and it drives you flippin mental trying to work out what's going on, especially with intermittent firing :bang: Then something clicked with a recollection that I wasn't the only person to have a Canon gun that flashes just once with an optical slave, then I soon found Michale Bass' site, and the answer.

What I can't figure out is why Canon does things the way they do, especially if Classcams confirms that his Metz gun is not afflicted in this way with an optical slave. I thought this was an inherant problem with the way Canon's E-TTL2 system works, but it may be just specific to Canon EX guns :shrug:

To be fair, I am pretty sure that Canon is constrained by patent restrictions and there is certainly some truth in the rumour of an old Minolta patent (which might have been originally held by Vivitar?) about camera-to-flash communication, which was subsequently sub-licensed to Nikon. Whatever, we're still stuck with these workaround solutions and Mr Bass appears to make a good living out of resolving them for us

The cost of all these mods adds up (I've got four 580EX guns to sort, but only going to do two ) and I think I'm going to go for this one http://bp0.blogger.com/_CRxbBKkoqIY...AxI/92_PlWjmdts/s1600-h/CanonOpticalTrig2.jpg Basically just a slave plugged straight in to the magic connector, then into a socket in the foot that I'll have a go at DIY. It's the neatest fit, and cheapest, and you can swivel it front or rear for best light pick up - $55 inc the slave.

 

[HoppyUK]

I have bought twne last week,but with the falling pound 189 quid. Both guns on ETTL, fire one manually, second one fires. Fired them 3 times.

Cheers bud, but I'm still not clear - my Canon guns will do that.

Sorry to badger you, but have you actually triggered a Metz gun via an auxilliary optical slave (not the built in ETTL) and got it to fire more than once without resetting it?

 

[mick johnson]

The cost of all these mods adds up (I've got four 580EX guns to sort, but only going to do two ) and I think I'm going to go for this one http://bp0.blogger.com/_CRxbBKkoqIY...AxI/92_PlWjmdts/s1600-h/CanonOpticalTrig2.jpg Basically just a slave plugged straight in to the magic connector, then into a socket in the foot that I'll have a go at DIY. It's the neatest fit, and cheapest, and you can swivel it front or rear for best light pick up - $55 inc the slave.

Is it not a cheaper option to buy the RF-602 trigger that Flash sells on here, or, do they not work properley with a flashgun and studio lights together.

 

[classcams]

Here is the full picture. I put a slave on my Canon 430, set it to ETTL Fire my cano 5d using the pop up flash. The 430 fires Ok. Fire the 5d again, the 430 does not flash. Now I change over, one 48 on the camera and the other with the slave on pointing at the camera both set to ETTL. the camera fire the slave ok. Wait a few seconds try again and the slave fires again. try again for the third time and the slave fires again. No here`s the rub, we are back to the preflash firing the slave. If the slave is pointing to the camera this preflash from the slave upsets the setting of the camera so you get a shot that looks like there was no flash at all. So you need a slave plus a preflash cancel so the second flash from the camera triggers the slaves flash.

 

[HoppyUK]

Is it not a cheaper option to buy the RF-602 trigger that Flash sells on here, or, do they not work properley with a flashgun and studio lights together.

Yes, I think that radio will work fine and would be cheapest. It doesn't suffer from this SCR lock up thing. It would have to be a hybrid system with radio triggering the Canon gun, which would then fire all the other studio flash heads optically.

I just like the simplicity of optical but I'm probably getting too hung up on it, you're right

 

[HoppyUK]

Here is the full picture. I put a slave on my Canon 430, set it to ETTL Fire my cano 5d using the pop up flash. The 430 fires Ok. Fire the 5d again, the 430 does not flash. Now I change over, one 48 on the camera and the other with the slave on pointing at the camera both set to ETTL. the camera fire the slave ok. Wait a few seconds try again and the slave fires again. try again for the third time and the slave fires again. No here`s the rub, we are back to the preflash firing the slave. If the slave is pointing to the camera this preflash from the slave upsets the setting of the camera so you get a shot that looks like there was no flash at all. So you need a slave plus a preflash cancel so the second flash from the camera triggers the slaves flash.

That sounds like it's working no differently to the Canon flash. It's damn confusing

If you set both Metz guns to manual (not ETTL) and with the optical slave on the remote unit, I'm guessing that the remote flash will fire once. Then the SCR thing will lock up the slave and it won't trigger a second time without turning the flash off/on. If that is the case, then you would also need one of these little modifying devices from Michael Bass which cuts the residual current in the gun's hot shoe, allowing the slave to reset.

 

[classcams]

Nope, you are wrong. Everything set to manual situation normal, the Metz fires every time, the Canon just the once. I will spend tomorrow making a combined slave and preflsh killer. I made a single shot flash to use on the 5D which works great.

 

[HoppyUK]

Nope, you are wrong. Everything set to manual situation normal, the Metz fires every time, the Canon just the once. I will spend tomorrow making a combined slave and preflsh killer. I made a single shot flash to use on the 5D which works great.

That's interesting. So this single flash then lock up thing is a feature of Canon guns, not the Canon ETTL method of operation. Handy to know. Thanks for checking