Sunday, April 12, 2009

fire at will

Spent about 30 minutes today trying to figure out how to trigger my 3 small strobes. I've got a bit of a mix of lights and triggers - 3 pocket wizards, two canon speedlites (a 580EX and a 420EX slave only/ TTL unit) and a cheap, second-hand Nikon SB28. I've also got a set of radio poppers (thanks to the guys at Tricoast) and a Canon ST-ET2 transmitter. A bit of a mess really. The problem is, I can't easily trigger all 3 lights at the same time. I can easily trigger pairs of them, using the pocket wizards, to control the 580EX and one of the SB28 or the 420EX. I can use the ST-ET2 to trigger both the 580EX and the 420EX, with or without the radio poppers in the mix to remove the need for line of sight. But I couldn't get all three to trigger at the same time. Eventually today I worked it out - but it is still a bit of a mess.

I was able to use the pocket wizards to trigger the 580EX, in master mode, that then triggers the 420EX. That works fine. Then if I add in the SB28, also triggered by the pocket wizard, all three only trigger, if the SB28 is out of sight of the other units. The 580EX seems to communicate/ trigger the 420EX within the white light flash output - I thought it might have been IR, but it doesn't seem to be. So the SB28 firing at the same time confused the 420EX in to not firing. The solution was to use the radio poppers to trigger the 420EX, covering up its control window with some duct tape, so that it only sees the control pulse from the radio popper. Not really ideal, but it seems to work at least for now. Next step is working out how to control the output power levels, but mostly I was interested in using the 420EX and SB28 as background/ edge lights in this arrangement, so the power levels aren't too much of an issue.

The alternative is just to buy some more controllable Canon flash units. Tempting!

5 comments:

Anita Jesse said...

Yes, I think it's time for another Canon 420EX or 430EX. When will we get to see some of the photos taken with your ingenious lighting setup?

Anonymous said...

Interesting dilemma, but I am a bit confused. My 580 EX (master)/420 EX combo fire by IR, not optical triggering. You can test that by putting a wall between the two to block the IR.

A combo that comes to mind would be to use the ST-ET2 to trigger the 580 as master to the 420. One PW in the PC connection on camera to trigger another one on the SB28. I can't test this theory as I have no PWs and I don't know if the PC connection will work in conjunction with something hot shoe mounted.

If you are serious about buying another 420, I wouls suggest that you look for a good used 580 EX MI instead. I am down on the 420 as it has no manual output adjustment that I can find. If you are running manual it is al or nothing and at times I want to reduce the out put on that one unit.

I will check back for any progress, as I have somewhat the same gear.

My best, Steve Weeks

Gordon said...

Hi Steve,

Thanks for the questions. I think it is a common misconception about how the 580 controls slaves - it uses visible light pulses to control the slave flash. You'll probably see IR/ red light from the AF assist lamps, which isn't actually part of the flash power control.

The Photonotes page is a great resource:
'Fifth, 550EX, 580EX and 580EX II master units use visible light pulses to send their commands, which some may find distracting.'

It also explains why the other non-Canon flash triggering could block/mask/confuse the control signals.

The other issue with going to an ST-ET2 and additional canon flash is that you can only control the A:B group ratios, rather than A:B:C from an ST-E2 - which is fine if I wanted to use two 420's at the same power ratio, but otherwise a bit limiting. It is frustrating.

I haven't tried using the PW triggered from the camera - not sure if that is possible with a 1D body - there isn't a PC sync I don't think (but I'd need to check)

Anonymous said...

Hi Gordon,

Great resource link and I stand corrected. Thanks

If memory serves you use a 1D MKII. On mine the PC terminal is just above the Remote Switch terminal and under the same cover (top). The owners manual doesn't mention that if a hotshoe mounted device is in place that the PC terminal is non-active. Since I have no flash units that use PC I can't test this for you.

For small additional flash units I am going to try this one. http://www.mpex.com/browse.cfm/4,12311.html

Granted it only works in manual mode, but it that is fine by me. Connections are PC, mini and what I think of as a true optical slave (flash detection). The price is such that one could get two+ for the price of a new 430 EX. The output is slightly less than the 430, but I would use the 580 as key and any additional for accent.

I look forward to following your progress down the external flash lighting path.

My best, Steve

Anita Jesse said...

I'm going to throw this out there in case one of you cares to answer a question from a real dummy. Would my 580EX trigger a LumoPro LP120? (My camera is a 40D.)