by Sean Setters
About 8 years ago, I purchased a 4' x 6' (1.2 x 1.8m) softbox from eBay (they aren't even available anymore) and really liked the soft light it projected onto my subjects. However, the more I used it, the more I realized how impractical it was. The biggest problem was that the softbox's weight was too heavy for my studio strobes' spring loaded mounting fingers. The softbox would mount to a studio strobe under ideal conditions, but any movement of the softbox (repositioning, small gust of wind, etc.) would cause the it to dismount from the strobe and [usually] break the modeling light and/or flash tube in the process.
And even if the softbox stayed connected to the studio strobe, the studio strobes positioning handle couldn't be tightened tight enough to prohibit the softbox from slowly inching its way downward at the pivot point. The problems inherent to the weighty modifier meant that it was rarely ever used. That is, until I recently came across a solution to the problem.
The mountable speed ring will be especially helpful for anyone suspending a large softbox above a subject or with the modifier pointed downward at a significant angle as gravity will be pusing the strobe into the mounted speed ring instead of pulling the speed ring away from a traditionally mounted strobe. However, if planning to do this, it would likely be best to permanently affix the 3/8" stud to the mountable softbox with epoxy/glue. The mountable speed ring's risk-reducing design may be the most economical insurance you ever buy.
There are three versions of the mountable softbox currently available for compatibility with Paul C. Buff/Alien Bees/White Lightning, Bowens and Profoto. However, while I cannot confirm that this is the case, if you have a similar non-mountable speed ring with interchangeable mounts (most third-party speed rings are designed this way), then you may be able to swap out any of the mounts available to make it compatible with your own strobes.