Inconsistent remote control of flash guns...

[Walti]

I set up a photo booth for my daughters wedding, as follows:

EM-1ii on a tripod, with flash command unit set on top, set to "off" - ie fired before the shutter for command of remote flash guns.

FL 32R on stand with umbrella to left of subject
FL 32R on stand with umbrella to right of subject
FL 600R as fill in to right and high level with bounce
Slave flash to left at low level for fill in set to minimum output (fill in for long dresses)

The three Olympus flash guns were set to TTL auto and compensation was set at the camera.

When they all fired, exposure (with +2 stops on each of the FL 32R and +2 stops on exposure) gave very good results, but.... out of 370 photos there were a significant proportion where one or other of the two (and a few where both) FL 32 Rs didn't fire, giving uneven exposure.

Batteries were all new, and though some ran out during the evening they were swapped almost instantly.

Everything was left powered on continuously...

Camera was tethered to laptop using Olympus capture for the users to see what they were getting/had got...

Any clues to point to uneven firing of the system?

Whenever it was tested it worked perfectly, all photos seem to be consistent as to where people stood (give or take a few inches) but flash commander was seen by the flash sensors...

[Ross the fiddler]

Re: Inconsistent remote control of flash guns...

The output commander flash can be set to low, medium or high. What were you using? In brighter or more difficult situations I would choose High commander level (not including it in the exposure though) as those flashes (FL36R?) may not have been receiving enough level to trigger them.

[Graham_of_Rainham]

Re: Inconsistent remote control of flash guns...

My first thoughts would be the recycle time to full power. I too have had one or two occasions when batteries have not been fully charged, or one is not up to full current delivery capability and the recycle time changes significantly.

For situations as you have described, I have replaced the batteries with a DiY mains power supply.

[RobEW]

Re: Inconsistent remote control of flash guns...

I'll watch this thread with interest. I've had lots of erratic behaviour using RC mode (on E-M1 "classic"). I have a feeling that using light flashes as a way of communicating between the on-camera flash and other flashes is somewhat error-prone, depending on which way sensors on the off camera flashes are pointing, how close they are, other light in the area.

[Walti]

Re: Inconsistent remote control of flash guns...

The output commander flash can be set to low, medium or high. What were you using? In brighter or more difficult situations I would choose High commander level (not including it in the exposure though) as those flashes (FL36R?) may not have been receiving enough level to trigger them.

[Walti]

Re: Inconsistent remote control of flash guns...

My first thoughts would be the recycle time to full power. I too have had one or two occasions when batteries have not been fully charged, or one is not up to full current delivery capability and the recycle time changes significantly.

For situations as you have described, I have replaced the batteries with a DiY mains power supply.

[Ross the fiddler]

Re: Inconsistent remote control of flash guns...

You are using Eneloop batteries in the flash, aren't you? They are the best & especially the Eneloop Pro (shorter shelf life but higher power).

[Walti]

Re: Inconsistent remote control of flash guns...

Never heard of Eneloop - I’ve been using bunnies - sorry Duracell...

[Walti]

Re: Inconsistent remote control of flash guns...

Must admit - I don’t think it’s the batteries as the recycle time was good throughout the evening....

[MJ224]

Re: Inconsistent remote control of flash guns...

Eneloops claim to fame is that they keep a good charge when being left to a week/month or two before being used. So you can charge them, and they will be good when needed........

But as with most rechargables they don't have the punch a normal Duracell type battery..

I use them almost exclusively..........

[RobEW]

Re: Inconsistent remote control of flash guns...

...

One detail I missed was that the flash heads were turned backwards to fire into the umbrella and the body with the receiver was pointing forwards at the subject.

In some configurations this setup would make for a better line of sight from the on-camera trigger flash to the off camera receptors.

[Michael Sewell]

Re: Inconsistent remote control of flash guns...

Hi Walti

There are a number of factors that can interrupt an optically based triggering system. Some have already been mentioned such as batteries etc.

Even in a fairly low lit scenario, a ceiling spotlight can disrupt the sensor if it's immediately below the light. Oddly, the subject can interfere in event style work. One or more of your speedlights may be relying on a spike in the general ambient level, as opposed to being able to directly see the commander. If they are relying on the increase in light levels from a said direction, say the other side of the area, and your subjects are a larger group and obstruct more of that are, then it won't see a sufficient increase in light.

Were all your speedlight sensors pointed towards your commander, or at least pointed directly at another flash, which in turn was pointed at your commander?
Many forget to point the sensor at the commander, and twist the head towards the subject.

A "Get out of Jail" card, would be to use an onboard speedlight as commander, and fire towards the ceiling if low enough. The ceiling would provide an overall soft light, so it wouldn't create issues with the image, but the bounced command signal should reach other units far better. You can always turn down the onboard unit to -3.0, so it doesn't really add anything, but the bounced signal should still be seen better.

Optical systems are not the most reliable, and in an event scenario, notoriously so.
If you are intending to stay with TTL, it would be worth looking into the Cactus V6II system, as not only would you have far more reliable radio linkage, but also remote control over the speedlight output too.

[Michael Sewell]

Re: Inconsistent remote control of flash guns...

Honestly?

The easiest and most reliable way is to buy a cheap set of manual only radio triggers, and use your speedlights in manual mode.

Dead easy, and dead reliable

[Walti]

Re: Inconsistent remote control of flash guns...

It wasn't that good a post... so I've deleted this copy!

[Walti]

Re: Inconsistent remote control of flash guns...

Having looked through the photos again, it does look like intermittent communication with the slaves from the commander is the most likely issue, so many thanks for all the guides...

I don't recall there being a light above the one that failed most... but there may have been.

The "line of sight" for the commander to the slaves was via a bounce off the subject rather than direct so next time I need to be more careful about that. I will put it all back together to check how that works...

I'll do a write up for everyone so that hopefully others can learn from my errors...

The other issue I haven't got my head around is sorting the exposure correction out... IF I left the camera and kit to its own devices the result was at least two - probably more - stops under exposed, so I had +2 stops set to each of the main flashes, -1 stop for the fill ins, and +2 stops on the exposure compensation dial for the camera. The results when it all fired properly was a shadow free nicely exposed picture.

It was set up to be a user triggered system rather than a photographer standing over the set up... so given this - the results are great - just not 100%