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Archive 2013 · Canon Speedlites and Alien Bees
  
 
chas
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p.1 #1 · p.1 #1 · Canon Speedlites and Alien Bees


Can anyone tell me if it is possible to use Canon Speedlite 580EX to trigger both a 420EX and two AB 800's? I am trying to use one of the AB's in a softbox as the primary and one as an hairlight, and the 420 as the background light, and am shooting with a 5DM II.


Jun 20, 2013 at 10:46 PM
BrianO
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p.1 #2 · p.1 #2 · Canon Speedlites and Alien Bees


It can be done, but not easily.

The problem is that the normal way a Canon Master triggers a Canon Slave is by sending optical pulses from the Master, the first ones being command and control signals and the last one being the "fire now!" signal.

If you try to trigger a strobe with that system, the strobe will fire out of sync upon seeing the first preflash.

The way to do it is to set the on-camera Speedlite to Manual mode with Wireless set to "Off" so it doesn't send any ETTL metering preflashes or Wireless C&C preflashes, and then use the built-in optical sensor on the ABs and a Canon-compatible optical sensor plugged into a hot-shoe adapter on which the 420EX is mounted.

It's a lot easier to fire all of them with radio triggers. I am currently using the Yongnuo YN-622C system, which can fire Speedlites in ETTL or Manual mode, and trigger strobes through their PC jack.



Jun 20, 2013 at 11:50 PM
chas
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p.1 #3 · p.1 #3 · Canon Speedlites and Alien Bees


Brian, thanks for the quick reply. I agree with your opinion regarding firing all via radio, but I already have the old original AB transmitter set up, which will not support the Speedlites, and I do not have the $$ to spend on an entirely new RF setpup. Do you have any info on a hot shoe adapter and a Canon compatible sensor I would use for the 420?


Jun 21, 2013 at 12:45 AM
cgardner
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p.1 #4 · p.1 #4 · Canon Speedlites and Alien Bees


The 420EX is the earliest model EX flash and is ETTL only. Never owned one but I don't think there will be any way to adjust power levels if triggered with a third party trigger, except perhaps by covering it with ND gels.


Jun 21, 2013 at 01:08 AM
BrianO
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p.1 #5 · p.1 #5 · Canon Speedlites and Alien Bees


chas wrote:
...Do you have any info on a hot shoe adapter and a Canon compatible sensor I would use for the 420?


I wasn't taking into account that the 420EX is ETTL only; I was thinking of the 430EX. Maybe it will still work as a background light, and you can adjust the other lights around its output.

At any rate, here's the links for the optical slave and hot shoe that I have used (but with other lights, not the 420EX):

http://www.flashzebra.com/products/0274/index.shtml

http://www.flashzebra.com/products/0135/index.shtml



Jun 21, 2013 at 03:37 AM
gpop
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p.1 #6 · p.1 #6 · Canon Speedlites and Alien Bees


cgardner wrote:
The 420EX is the earliest model EX flash and is ETTL only. Never owned one but I don't think there will be any way to adjust power levels if triggered with a third party trigger, except perhaps by covering it with ND gels.



one way is to use the radio popper 'cube' thingy and the 'Jrx' transmitter.


as far as the triggering issues goes, perhaps you can shield the 580's pre-flash from the AB, and force the slave speedlite to trigger the AB optically? maybe more trouble that it's worth.







Jun 21, 2013 at 06:50 PM
BrianO
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p.1 #7 · p.1 #7 · Canon Speedlites and Alien Bees


gpop wrote:
...as far as the triggering issues goes, perhaps you can shield the 580's pre-flash from the AB, and force the slave speedlite to trigger the AB optically?


The slave will also emit a preflash in ETTL mode; it's two-way communication between Master and Slave, including metering the Slave's output.



Jun 21, 2013 at 07:24 PM
 

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gpop
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p.1 #8 · p.1 #8 · Canon Speedlites and Alien Bees


BrianO wrote:
The slave will also emit a preflash in ETTL mode; it's two-way communication between Master and Slave, including metering the Slave's output.



that's a good point, hadn't thought of that.
drat.

I should have known the the ett-l flash would have to pre-flash for metering, but does it actually communicate with the master ? (not that it matters in this case)



Jun 21, 2013 at 07:44 PM
BrianO
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p.1 #9 · p.1 #9 · Canon Speedlites and Alien Bees


gpop wrote:
...does it actually communicate with the master ?


Yes, in that the Master will command the Slave to fire a metering flash and then watch for the result, adjusting the output as needed.

Chuck Gardner has posted this flowchart from Canon several times; I think it does a good job of showing the process:








Jun 21, 2013 at 07:49 PM
chas
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p.1 #10 · p.1 #10 · Canon Speedlites and Alien Bees


But if I put the 580 in manual mode, and slave the 420 using a flashzebra setup that BrianO had identified, would not all devices then fire off the single flash the 580 would emit? I can set the flash power of the 580 and the AB's, and will need to use gells to control the 420 background light. Am I correct in this thought process, or am I being to simple in the approach?



Jun 21, 2013 at 10:15 PM
cgardner
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p.1 #11 · p.1 #11 · Canon Speedlites and Alien Bees


I mixed ABs and speedlights before I got 4 AB800s and found it's a PITA logistically adjusting power relative to each other and waiting for 3-6 sec. for the speedlights to recycle.

One of the ABs centered about chin level back under the camera as fill will also illuminate the background to the point I usually don't use a separate background light for dark background shots.

I'd suggest trying the ABs and Fill and Key with the 580ex which you can adjust manually as your hairlight and forego the background light. To fire the 580ex manually with an optical or radio trigger (via a hot shoe extension cable) set as follows:

1) Place switch in "Slave" mode

2) Press and hold the MODE button for 2 sec. until the M indicator blinks.

3) Use Set button and turn wheel to set the power.

This is shown in the 580ex manual in the manual control section but not explained very clearly.

Edited on Jun 22, 2013 at 11:59 AM · View previous versions



Jun 21, 2013 at 10:55 PM
BrianO
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p.1 #12 · p.1 #12 · Canon Speedlites and Alien Bees


chas wrote:
But if I put the 580 in manual mode, and slave the 420 using a flashzebra setup that BrianO had identified, would not all devices then fire off the single flash the 580 would emit?


I think so.

The only question is about the 420EX. Will it fire from the center-pin sync-only signal of the Flash Zebra adapter, or does it require a coded signal through the ETTL pins? I just don't know.



Jun 22, 2013 at 03:41 AM
cgardner
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p.1 #13 · p.1 #13 · Canon Speedlites and Alien Bees


BrianO wrote:
I think so.

The only question is about the 420EX. Will it fire from the center-pin sync-only signal of the Flash Zebra adapter, or does it require a coded signal through the ETTL pins? I just don't know.


Center pin carries the "fire main flash" signal. It will fire but at full power. You could regulate output with ND gel but need to wait 5-6 sec. for recharge. Technically feasible, but not practical logistically.

Master and camera communicate intelligently via the four extra TTL pins in the hot shoe, but communication between master and slaves in the Canon optical system is master to slave only. Slaves do not communicate back to master, the camera body simply meters their pre-flashes in coordination with the master telling the each group to fire them individually.

With optical system when a flash is in SLAVE mode bigger red AF assist lamp blinks as a "ready" indicator on the slaves. It has no role in the metering, it's just an "idiot" light to tell the photographer not to shoot while the Slave is recharging between shots. In some situations like event photography with dual flash I'll cover most of it with black tape because the blinking is distracting.

If you use the Canon flashes in optical mode you'll note when slaves are firing at max output it will stop blinking for several secs. as slave recharges. There is nothing to prevent the camera from firing another shot before the slave is ready which produces inconsistent exposure. What I do is watch the slave indicator for the first few shots with any set-up to get an idea of the recharge time of the slave then pace my shooting accordingly so as not to out pace the flashes. I never have a problem with inconsistent exposure that way.

That's actually a rather clever design feature because the AF assist is directly above the sensor window on the slave that must see the coded flashes from the Master and the pilot "ready" light on the back isn't visible when the control window is pointing at the camera. If the photographer can see the flashing AF assist light on the slave when using the Master flash in the hot shoe the Master will be able to trigger the Slave reliably. That's more critical outdoors where there is no bounce and line of sight contact between Master and Slave sensor window on the front of the base is needed. Indoors the control signals will bounce off walls and ceilings and can even trigger a flash in another room (I have tests in my Canon tutorials which illustrate that).

When using a Slave the front of the base should first be aimed at the Master then the flash head swiveled to the subject for the best Master > Slave communication. The failure to realize that is why many Canon flash users have performance problems with them and use radio triggers.

So if mixing you 580ex in SLAVE mode with the "M" light blinking as suggested watch the ready AF assist "ready" light and pace your shooting accordingly. You'll find that's a PITA because the ABs will be ready again almost immediately.

A significant difference / improvement with the RT models in addition to better signaling range and no line of sight limitation is that the Slaves do transmit "ready to fire status" back to the Master flash. I'm not sure if it acts as an inter-lock to prevent the camera from taking a shot unless the flash is ready or simply flashes a red indicator in the viewfinder of the exposure wasn't adequate (which is the case with the optical system).



Jun 22, 2013 at 11:58 AM





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