Why are my studio monolights not firing in a specific environment?

Question

I have three studio flashes (Mettle ME-400 monolights), activated using a Jinbei trigger and a receiver on one light, with the other two set to use an optical slave mode.

The lights were flashing without issue during a photoshoot on Thursday. On Friday I tried a new set up at my friend's large dance studio with three large soft-boxes (and gels) and I struggled to get all three lights firing together.

I tested all the lights at home today (Saturday) and they flashed fine/consistently again. I'm deducing that it must've been the environment - large space, one black wall; or the soft-boxes/ gels, that meant the sensors weren't picking up on the flash. Any advice to understand and remedy the situation would be appreciated.

Answer 1

Optical triggering can be a problem over large distances, in bright environments, and in situations where things block or absorb the light (softboxes and black walls).

IMO, you really should be using radio triggering. The ART1-G is an AC powered radio trigger specifically for the ME400. But I would probably be inclined to go with a "better" battery based wireless control system like Godox instead for about the same cost.

Answer 2

You probably ran into issues with line-of-sight requirements with the optical sensors on the two lights that weren't attached to the receiver.

Light has to travel directly from the strobe with the radio receiver to the red sensor under the handle of the other two strobes for them to fire. If the radio-equipped strobe was in front of the other two strobes, your softboxes were shading the sensor from "seeing" that light, and the black wall stopped light from bouncing its way around to the sensor, that's what probably caused your issue.

The easiest way around this is to purchase two more matching Jinbei receivers and have all three of the lights fire remotely from radio, rather than use optical slaving.

You could also consider purchasing strobes that have built-in radio remote control, such as Godox DP400 IIIVs or the Jinbei DMII-5, where you wouldn't have to attach a receiver, and you'd have remote power and modeling light on/off control over the strobe from the transmitter. You may even be able to integrate in other types of lights like battery-powered location strobes or speedlights in those two radio systems.

But without purchasing anything new, the only way to mitigate this might be to make sure the strobe with the radio receiver is always placed behind the other two strobes, so their sensors have clear line-of-sight to its bulb or the face of its modifier.

Answer 3

Complementing the other answers, here are some options you have.

Option I. Connect an additional radio receiver to the other lights.

Option II. There are optical sensors that can be connected to the flashes using a cord. Think of them as an extensor of the built-in optical sensor.

https://www.google.com/search?client=firefox-b-d&q=optical+slave+sesor+for+flash

Option III. DIY hacks.

I used to use optical slaves and I used some tricks depending on the reason the optical sensor is not working.

1. The sensor receives light, even on an interior, for example, there is a lightbulb above it, so it does not see the small lightburst of the other flash.

• Make a small tent, made of cardboard and some electrical tape (which is very easy to remove) with an opening directly to the other flash.

2. The sensor is actually in the dark, but there are dark walls around it.

• Make a "wall" with white cardboard or even aluminum paper so it reflects some more light to the sensor.

• If it is really problematic, you need to put a bigger white reflector, if you have some foamboard or white Vcard, use it.

But that was before the radio receivers. It is better to put one on every light so you are not limiting the way you use the softbox.