While there are quite a few solutions on the market today to mount more than one speedlight on a light stand, most of them are designed to be used with an umbrella. To find a simple setup to fire multiple hot-shoe flashes into a softbox seems to be not as simple. The recently released LumoPro LP739 Double Flash Speedring Bracket tries to fulfill the photographers' need and let them use virtually any standard softbox with two speedlights.
Before going into more details about the LumoPro flash bracket, let's pause for a seconds and think why you would want two speedlights in a softbox instead of one. There are few reasons for that. One obvious reason is that two identical flashes firing together double the maximum light output, which means one full additional f-stop of power.
Another reason is the faster recycling times, when you dial down the power of your speedlights. For example, if you set both flashes to half the power, the combined light output will be equal the maximum output of a single flash. However, since the flashes do not fully discharge in this case, they will recycle much faster. Additionally, if you fire your flashgun continuously with minimal intervals, they are much less likely to overheat when stopped down. (See, for example, our Nikon overheating test).
So, by using "paired" speedlights, you can double the maximum light output, get faster recycle times, and reduce the chances of flash overheating.
Now, let's get back to LumoPro LP739 Double Flash Speedring Bracket. The design concept is quite elegant. Many modern lightbanks mount on a standard 7 3/8-inch speedring, so LumoPro engineers came up with a way to modify the speedring to hold two speedlights. According to LumoPro, the LP739 Double Flash Bracket is compatible with most softboxes on the market today including LumoPro, Creative Light, Interfit, Profoto, Paul Buff, Westcott Standard, and other softboxes.
Essentially, LumoPro LP739 is a speedring with two arms that attach to its sides. The side arms feature cold shoes, and they can be extended to accommodate flashes of different sizes.
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We like that the speedring has platforms and "guides" for the side arms to make the assembly easy. Another nice touch is the rubber pads on the arms, which help secure the cold shoes in place. The whole unit looks and feels very well-built.
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We also like that all four screws are big enough to be used comfortably. However, we wish that two of the four that attach side arms to the speedring were made longer to stick out more, which would make the assembly even easier.
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The LumoPro Double Flash Speedring Bracket is not only designed to work with a wide range of hot-shoe flashes but also with various radio triggers paired with the flash guns. In the images below, you can see two Canon Speedlite 580EX II flashes with PocketWizard FlexTT5 fitted onto LumoPro LP739 and used with an octabox.
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We found, however, that the side arms of the LumoPro bracket were just a few millimeters short to mount two Canon Speedlite 580EX II units with RF filters for FlexTT5 triggers. Granted, stacking a radio trigger, RF filter, and a speedlight is not something you would want, but with 580EX II flashes, you have to do it to increase the triggering range of the PocketWizard FlexTT5's. Note, Speedlite 580EX II is the only flash that requires RF shielding, but it is a popular flash, so some users may face the fact that it's not possible to use two of these flashes with RF socks with this LumoPro bracket. There are workarounds, however, like having the triggers connected via a TTL cord, for example. In any case, we don't see this as a deal breaker or even a major issue, but it would be nice if LumoPro could make the arms just a bit longer.
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LumoPro LP739 Double Flash Bracket comes with a carrying case, which has a surprisingly thick padding. The speedring and the side arms can be secured inside the case with the Velcro tabs. The case is fairly large, and we were happy to see that it actually had enough space to carry the two speedlights you would use with the bracket (see the images below). If you are going to do that, however, please make sure to have the flashes in their protective pouches. Otherwise, you are going to damage them.
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To summarize, LumoPro LP739 Double Flash Speedring Bracket allows you to use speedlights with the standard softboxes you may already have. The design is elegant in its simplicity. The build quality is excellent, and we had no problem trusting the bracket to hold our flashes. LP739 is compatible with a wide range of flashes and radio triggers, as well as many brands of softboxes. The included carrying case can also accommodate two speedlights in their protective pouches, which can free up some space in your gear bag.