Canon EX multi-flash questions

[tim]

I just want to check something before I go ahead and order another couple of flashes... if you have a 550EX on-camera and a 580EX off to the right, can you tell the 550EX not to flash and tell the 580 to flash? I suspect you can but i'd love confirmation if someone can give it to me.

2nd question: same setup as above, 580EX is on a stand outside pointed into a silver umbrella on camera right about a meter or two to my right, will the IR signal reliably trigger the 580? I guess what I really want to know is where the IR signal to fire is transmitted from, and where the IR receiver on the other flash is fitted. If not I guess i'll get some cheap ebay radio slaves.

Last question: if I want to add a Sigma 500 Super as a hairlight inside, will it be reliably trigger by IR if it's behind the person? How about in optical slave mode?

[Joe R]

1: Yes - you can turn the Master off, but still trigger a slave.
2: Indoors no problem as the signal bounces around. Outdoors you need line of sight.
3: Haven't used Sigma flashes.

[tim]

Thanks Joe. What parts of the flash need line of sight? ie does there have to be line of sight between the front of both flashes, or as long as they can see each other on any side it's ok?

[robertwgross]

On all of these Canon Speedlites, there is an obvious red lens on the bottom part of the flash unit, above the "foot". That is the area where the autofocus assist red pattern is emitted, if you are doing that. Also, that is the area where the different units "talk" and "listen" to optical data between units. As long as those red lens areas can see each other, you are in good shape. If they can't see each other, but they can see the data pulses bouncing off something, then you are still in good shape. If they can't see each other, and if you are outside or spread out so far that they can't see any data pulses bouncing, then you are in trouble.

This kind of arrangement would be terrible if there were no means of swiveling the bottom of the unit undependently from the top. But, there is, so it works. So, you swivel the bottom of the units around to face slaves toward masters and then swivel the flash head tops of the units to meet your subject.

---Bob Gross---

[tim]

Thanks Bob, that was what I guessed but good to have it confirmed.

Here's my model setup: 550EX on camera either not firing or at FEC-2, 580EX pointing into a silver umbrella about 1-2 meters to my right, outside. There's no way the 550EX will trigger the 580EX, correct? So I guess i'd need a set of radio slaves? Of course then I lose ETTL :( In that case I might as well get cheap dumb Vivitar units and a flash meter.

[robertwgross]

There's no way the 550EX will trigger the 580EX, correct? So I guess i'd need a set of radio slaves?

Why do you feel that way?

The 550EX has some wireless transmission specifications. Indoors, approximately 12-15 meters. Outdoors, approximately 8-10 meters (because there is less chance for the data pulses to bounce and get there).

If you can get the red lenses to look at each other, then you are set. If you have one recessed so far into an umbrella that they can't see each other, then you may have a problem. There is probably some tricky way that you could rig up a mirror to bounce the data over better, but that seems kind of hokey.

---Bob Gross---

[tim]

I just imagine that it would be difficult to get the IR transmitter and receiver to line up if one's facing forwards on the camera and one's to meters to your right faced into an umbrella. Even if you mounted the flash kinda sideways on the light stand the one on the camera's still facing forwards not at the other one. Or does the IR leak sideways enough that it works?

Edit - the STE-2 specs say coverage of "+/-40 degrees horizontal and +/-30 degrees vertical", so I guess the umbrella would have to be in front of the camera, with enough of the flash in line of sight that the signal can go straight. I can imagine how that'd work.

[accord]

Last question: if I want to add a Sigma 500 Super as a hairlight inside, will it be reliably trigger by IR if it's behind the person? How about in optical slave mode?

As far as there are reflective surfaces, the Sigma (also applied for Canon EX) should receive the IR signal.

You will run into difficulty if you configure teh Sigma as optical slave. It does not talk with the master as it does not configure as ETTL slave. It will fire twice due to the pre-flash of ETTL, the second fire may not have enough power for your purpose. You have to manually configure the metering of this optical slave.

[tim]

Yeah, if I go for the optical slave mode i'll have to go to full manual with the other flashes. That means i'd need a flash meter... there's one on my wish list...

[robertwgross]

I just imagine that it would be difficult to get the IR transmitter and receiver to line up if one's facing forwards on the camera and one's to meters to your right faced into an umbrella. Even if you mounted the flash kinda sideways on the light stand the one on the camera's still facing forwards not at the other one. Or does the IR leak sideways enough that it works?


Go re-read what I wrote previously. The two parts of a flash unit swivel independently of one another. You can have the flash pointed out the front and the red lens pointed out the left or right or back. There is no leaking to it.


Edit - the STE-2 specs say coverage of "+/-40 degrees horizontal and +/-30 degrees vertical", so I guess the umbrella would have to be in front of the camera, with enough of the flash in line of sight that the signal can go straight. I can imagine how that'd work.

That's completely irrelevant. We are not talking about the STE2 here.

If you check it, the 550EX specifications are these:
Transmission angle: Horizontal: approximately 80 degrees, Vertical: approximately 60 degrees.

It sounds like you are not interested in this equipment and you are trying to make up excuses why it won't work. That's OK.

---Bob Gross---

[robertwgross]

As far as there are reflective surfaces, the Sigma (also applied for Canon EX) should receive the IR signal.


I find that the reflective indoor surfaces work OK most of the time, but they are a little unpredictable. Outdoors, reflective surfaces work somewhat less predictably than that.

---Bob Gross---

[tim]

Go re-read what I wrote previously. The two parts of a flash unit swivel independently of one another. You can have the flash pointed out the front and the red lens pointed out the left or right or back. There is no leaking to it.


That's completely irrelevant. We are not talking about the STE2 here.

If you check it, the 550EX specifications are these:
Transmission angle: Horizontal: approximately 80 degrees, Vertical: approximately 60 degrees.

It sounds like you are not interested in this equipment and you are trying to make up excuses why it won't work. That's OK.

---Bob Gross---

I read what you wrote, and I understand it fine. The IR transmitter on the on-camera flash must always face forwards, in the same direction that the lens is facing. This means that slave flash must be in front of you, within the 80 degree arc that the transmitter covers.

Here's what I was thinking before: Stand up and stretch out your right arm to your right. That's where I was picturing the 2nd flash and umbrella would be, only a little further away. That won't work because of transmission angles. If I put the flash stand/flash/umbrella within the arc that the transmitter covers, with the receiver pointed towards the transmitter, and the flash head pointed into the umbrella, that should work. The problem was I was thinking of the umbrella being in the wrong place for a setup this small.

Thanks for your help.

[robertwgross]

I read what you wrote, and I understand it fine. The IR transmitter on the on-camera flash must always face forwards, in the same direction that the lens is facing. This means that slave flash must be in front of you, within the 80 degree arc that the transmitter covers.


If you want to restrict yourself that way, then that is OK.

If I want to have a Master at the camera, and if I want it to flash forward, yet I want it to emit wireless data to a slave out at the side, then I stick the Master on a flash bracket and crank it around to any side direction I want. Like I stated, the two halves of the flash unit move independently, so you can aim part here and part there.

---Bob Gross---

[tim]

If you want to restrict yourself that way, then that is OK.

If I want to have a Master at the camera, and if I want it to flash forward, yet I want it to emit wireless data to a slave out at the side, then I stick the Master on a flash bracket and crank it around to any side direction I want. Like I stated, the two halves of the flash unit move independently, so you can aim part here and part there.

---Bob Gross---

Now everything falls into place, I didn't even think of that. Thanks Bob, very helpful :)

[robertwgross]

When I went for the first time as "second shooter" with a wedding photographer, I spent most of my time watching him and watching the gear that he used. Then before the second wedding, I had surrounded myself with all of those little bits of this and that, flash bracket, reflectors, etc. By the time we got to the third or fourth wedding, I saw how each piece was going to fit together in the puzzle. Ninety percent of the time, you can just shoot with standard equipment arranged in some standard fashion. However, when the tricky 10% scene shows up, you have to twist your gear around so that you can get the shot uncompromised. Once you get to your tenth wedding, you will have the solutions boiling out of your brain before they even show up. By the time you get to your twentieth or fortieth wedding, we will change your name to Bloo Dog or something.

All I said will make sense to a left-brain individual. If you are the right-brain type, then you might want to shoot the scene without flash so that you can capture the mood.

---Bob Gross---

[tim]

It'd be great to go and watch a seasoned professional shoot weddings, i'll have to try to find someone who would do that. Perhaps my photographer ex-teacher will bring me along one day.

[robertwgross]

It'd be great to go and watch a seasoned professional shoot weddings, i'll have to try to find someone who would do that.

There were two of us working professional positions in one company, and I got to know the other guy, and he showed me some of his large prints. He barely had enough time to work the job and also shoot weddings on the weekends once a month. Once he left the company, I stayed in touch. Once I left the company, I arranged to go on his next wedding as a "gopher". Then we struck up a better arrangement. Unfortunately, he used all Mamiya and Nikon film equipment, and I was strictly digital.

Actually, that was kind of a good arrangement where one type of technology backs up the other. For a while, he only used me as "insurance" in case the bride was tossing the bouquet and he was in the mens room.

---Bob Gross---

[tim]

Sounds like a good system. I'll have to talk to the guy who did my beginners course who's a pro shooter who does weddings among other things. I'm taking him for lunch at a fancy resturant next week to thank him anyway...