580/550/420ex and hot shoe light slaves

Canon EF 100mm f/2.8 USM Macro

11/28/2004 08:55:59 PM · #1

I am trying to use a 580ex and a 420ex (and I believe this also applies to the 550ex) speedlights as remote strobes in a studio setup.

I can't use my ST-E2 as this fires some sort of pre-signal that fires off my other main studio strobes too early. The same thing happens if I use the 580 on the camera as a master unit, in triggering the 420 it sends out a pre-flash and triggers the main strobes too early. Also, I do not want to 580 on camera anyway (580 in manual works, but only on camera).

So, I purchased a couple of light slave sensors, the little hot shoe mount thiungs with the photo cell (and removed the ST-E2 completely from the equation).

This will fire the 580 and 420 perfectly, from the light from the mian studio strobes.

However, the 580/420 then need to be turned off/on between every single shot, which becomes unworkable for what I want.

Has anyone else come across this and found a solution? Or maybe knows of a make of hot shoe light slave thingy that they KNOW works with these speedlights?

All I can find about it on the net is that others have this problem, but I have yet to find a solution.

Thanks

Spork99

OM System OM-1

11/28/2004 09:54:27 PM · #2

It sounds like you are firing your studio strobes from your camera using the PC terminal and the Canon units from the optical slaves. I think what you need to do is fire the studio strobes using the slave and use the ST-E2 to fire the Canon Flashes.

This slave, and other similar to it will ignore the pre-flashes emitted by the 420/550/580 flash units.

11/28/2004 10:02:30 PM · #3

I've missed the point of why you've got to turn off te 580/420 is this to save batteries?

I imagine they will last for ages on a good set of NmHi batteries, as do most modern flashes?

Or is there something I've missed.. (More than likely. :-) ).

Cheers, Me.

11/28/2004 10:15:28 PM · #4

Originally posted by Spazmo99:

The studio strobes have their slave sensor built in, so I've tried all combinations. But yes, that is the latest way I was trying.

However, that little unit you have there looks promising.

Do you know Spaz if this would work: Turn off the light sensor on the studio strobes. Each strobe has a PC Sync socket, so plug one of those units into each studio strobe. Then use the ST-E2 etc as per normal.

I THINK that is how it looks like that would work, but can you confirm that?

Also, are you sure the ST-E2 doesn't trip it anyway with whatever it is sending out to the falshes (i.e. some sort of warm up infra-red beam rather than a physical flash).

Originally posted by ohmark:

I've missed the point of why you've got to turn off te 580/420 is this to save batteries?

I've got to turn them off after each shot, not for battery life at all, but because once they fire once they simply will not fire again until switched off, even if you hit the test button (or whatever it is) on the back of the unit.

11/28/2004 11:01:14 PM · #5

Originally posted by Natator:

Even in manual mode? Yikes.

Is that normal for the ex series flashes? I assume so if it's happening with the 420 and the 580.

11/28/2004 11:05:07 PM · #6

This thread sheds some light... Not much help though.

In a word, bummer...

Canon EF 100mm f/2.8 USM Macro

11/28/2004 11:37:56 PM · #7

Originally posted by ohmark:

This thread sheds some light... Not much help though.

In a word, bummer...

Yeah :(

Thanks for that link, it does indeed shed some light, even if it does not provide an actual solution.

I think Spazmo's suggestion might be the way to go, but I somehow need to check, before I order as I am ordering from overseas, that:

1) That optical unit will not get triggered by the ST-E2 "pre-flash"

2) That it will actually fire studio strobes

Spork99

OM System OM-1

11/29/2004 12:13:28 AM · #8

Originally posted by Natator:

Originally posted by ohmark:
This thread sheds some light... Not much help though.

In a word, bummer...

Yeah :(

Thanks for that link, it does indeed shed some light, even if it does not provide an actual solution.

I think Spazmo's suggestion might be the way to go, but I somehow need to check, before I order as I am ordering from overseas, that:

1) That optical unit will not get triggered by the ST-E2 "pre-flash"

2) That it will actually fire studio strobes

1) The slaves are not sensitive to IR light, which is what the
ST-E2 "preflash" and communication signals are.

2) If you buy one that has the same socket as your sync connection on your strobes, you should be OK.

You can also "hardwire" all of your strobes together so that you would only need one slave, but that means buying long sync cables.

This is the main reason why "H" plug syncs are nice to have on strobes, you can build a network of hardwired strobes with nothing more than really long household extension cords and a few 2 prong adapters. The bad thing is that it makes it possibe to connect the sync terminal of your strobe unit to household current and that is a BAD thing.

What studio strobe units are you using?

11/29/2004 02:34:11 AM · #9

Originally posted by Spazmo99:

1) The slaves are not sensitive to IR light, which is what the
ST-E2 "preflash" and communication signals are.

Ummm, yeah they are.... One specific thing you can do with them is use an IR pass filter on an on-camera manual flash to trigger the slaves. I do that with my G5 quite often, as it gives me a cheap 'cordless' flash trigger.

The ones I use that came from Ebay can be triggered with the TV remote control if you hold it 3-4" away from the sensor lens.

edit: just playing my 20d... In manual mode the flash isn't, the sodding thing pre-flashes, so you can't even use it to trigger slaves. Mutter mumble. The manual says it actualy does an auto-exposure even though the camera is in manual mode.

Natator: I assume you can actually do a manual power setting single flash with the 580ex?

Originally posted by Spazmo99:

The bad thing is that it makes it possibe to connect the sync terminal of your strobe unit to household current and that is a BAD thing.

ZAP! :-).

Message edited by author 2004-11-29 02:41:05.

Canon EF 24-70mm f/2.8L USM

11/29/2004 03:08:29 AM · #10

Originally posted by Spazmo99:

2) If you buy one that has the same socket as your sync connection on your strobes, you should be OK.

You can also "hardwire" all of your strobes together so that you would only need one slave, but that means buying long sync cables.

This is the main reason why "H" plug syncs are nice to have on strobes, you can build a network of hardwired strobes with nothing more than really long household extension cords and a few 2 prong adapters. The bad thing is that it makes it possibe to connect the sync terminal of your strobe unit to household current and that is a BAD thing.

What studio strobe units are you using?

My units are Elinchrom EL500's, made in Switzerland.

The problem, as I just realised, is that they have an Elinchrom specific plug at the strobe end of things ... which means those units you showed me won't fit.

I have already asked about daisy-chaining them with sync cords and apparently you can't do it as there is no such adapter :(

Looks like the idea with that optical slave won;t work because of the fittings :(

Originally posted by ohmark:

Natator: I assume you can actually do a manual power setting single flash with the 580ex?

Yup, set it to manual and it works perfectly and triggers the strobes perfectly. Only problem is I am then limited to the flash being stuck on the camera, which is what I am trying to work around.

hughletheren

Canon EOS-7D

11/29/2004 05:45:23 AM · #11

Surely you can use flash exposure lock (page 97 in the manual)? I would expect this to lock the flash exposure and eliminate the pre-flash, allowing you to use the ST-E2? Just thinking aloud. . . .

Spork99

OM System OM-1

Canon EF 100mm f/2.8 USM Macro

11/29/2004 09:15:16 AM · #12

Originally posted by ohmark:

Originally posted by Spazmo99:
1) The slaves are not sensitive to IR light, which is what the
ST-E2 "preflash" and communication signals are.

Ummm, yeah they are.... One specific thing you can do with them is use an IR pass filter on an on-camera manual flash to trigger the slaves. I do that with my G5 quite often, as it gives me a cheap 'cordless' flash trigger.

The ones I use that came from Ebay can be triggered with the TV remote control if you hold it 3-4" away from the sensor lens.

Hmmmm. I never ran into that problem with the little bugs, but I can imagine that some might be sensitive to IR pulses.

Originally posted by ohmark:

Originally posted by Spazmo99:
The bad thing is that it makes it possibe to connect the sync terminal of your strobe unit to household current and that is a BAD thing.

ZAP! :-).

Yeah, tell me about it, that's one lesson you only have to learn once.