Update 29 Nov 2011: Dutch photographer Chiel van Diest has tipped me off about this Meike Elinchrom-Bowens adapter (pictured right) available from the Netherlands. A much easier and cheaper option!
For a long time I have wanted to own an Elinchrom Rotalux Deep Octa. As one of the best beauty reflectors on the market, it's punchy light picks out bone structure and body contours while still maintaining enough wrap-around to avoid unpleasant shadows. The octagonal shape also ensures that round catchlights are reflected in the eyes. It essentially acts like a very large beauty dish, only lighter and far more portable - the whole thing can be collapsed like an umbrella when not in use.
The only problem? Rotalux Octas can only be used on Elinchrom and Profoto lights. I own Bowens... That wasn't going to stop me though! Defiant, I decided to dust off my power drill and embark on my own conversion.
I owe a huge thanks to fellow photographer Lloyd Stretton, who blazed a trail with his own conversion. His experience gave me the confidence to lay down £200 and tear apart my new Octa with a power drill!
DISCLAIMER: Modifying your Octa will invalidate its warranty. You do this at your own risk. I am not responsible for any damage or financial loss that may result!
Anatomy of the Elinchrom Octa Speedring
The octa is attached to the light via a metal speedring. It's a really fine piece of engineering.
A central adapter ring is sandwiched between two identical pieces of metal. This ring mounts the Octa onto the light. Eight spring-loaded sockets circle the outside and accept the metal ribs that give the octa it's shape. All this is held together by sixteen rivets.
What we want to do is replace the inner Elinchrom adapter ring with one that can be fixed onto a Bowens light. Pictured below is a Bowens S-fit adapter I bought from my local Calumet store.
First of all though we need to crack open the speedring, and this means removing the rivets. Although each one is 4mm in diameter, I recommend using a power drill with a slightly larger bit.
The idea is to drill into the rivet just enough to sever the connection between its shaft and end-plug. A counter-punch and hammer can then be used to knock out the rivet completely. In practice one may want to drill down further and create some give.
Should it go well, one is rewarded with a fresh, clean hole.
That's the easy part.
The hard part is machining the Bowens S-fit adapter ring so that it sits comfortably within the metal enclosure. The inner Elinchrom ring is 128mm in diameter; the S-fit ring on the other hand is 139mm. Fortunately I found a metal workshop nearby that agreed to sand-down the excess metal.
The inner Elinchrom ring is pretty chunky though and there is a good chance its replacement will be thinner. In this case the internal locking clamp may fail to bite. Mounting and detatching the octa can be very difficult if the inner ring is too slack. The solution however is relatively straight forward: File down the internal clamping piece until it does its job.
Finally, we use sixteen 20mm M4 "Slotted Pan Head Machine Screws with Nuts and Washers" to replace the rivets.
Attaching the Translucide Deflector
A thick, heat-resistant translucent disc comes with the Deep Octa. It's purpose is to block the intense, unflattering glare of the flash bulb. The "Translucide Deflector", as it is called, normally attaches to Elinchrom lights with a specially designed extension rod that plugs into the body. However our Bowens doesn't have the necessary fitting. We will have to improvise.
In this case I borrowed a trick from my beauty dish, which operates under a similar principle. Using a simple system of springs, key rings and 1mm galvanised garden wire - not to mention a little drilling - I was able to suspend the deflector exactly where I wanted it. The springs keep the deflector taut and allow easy assembly - one simply has to stretch the spring a little to hook on the wire. The key rings are an additional convenience, again aiding assembly. Likewise, everything can be dismantled painlessly. The springs remain on the metal ribs.
