After seeing yet another thread regarding Elinchrom’s digital readout, I thought I’d post an explanation to put an end to any lingering mystery.
The decimal power reading is based on the Joule (or Watt-second), which is equal to 6.25 x 10^18 electron-volts. The scale is divided by 10^18 to proportionalize it to a usable scale.
As a result, if Elinchrom’s digital power display is represented as Y and the energy discharged is represented as X, a conversion can be achieved to determine the number of Joules (Watt-seconds) as follows:
X = (6.25)(2^Y)
Therefore, when the Elinchrom digital display reads Y=5, this translates to an energy discharge of X=(6.25)(2^5) = 200 Ws. Similarly, when the Elinchrom digital display reads Y=4, this translates to an energy discharge of X=(6.25)(2^4) = 100 Ws.
Since the energy relationship is absolute, conversion the other way is also possible. The Elinchrom digital power designation (Y) can be derived from the discharged energy (X) as follows:
Y = [Log (X/6.25)]/[Log(2)]
Therefore, if the strobe is set to discharge X=600 Ws of energy, this translates to an Elinchrom designation of Y=[Log(600/6.25)/[Log(2)] = 6.58. Similarly, a strobe discharge of X=250 Ws translates to an Elinchrom designation of Y=[Log(250/6.25)]/[Log(2)] = 5.32.
Elinchrom is not the only company that uses this designation. But they are some of the best-designed units that take advantage of the scaled designation to allow their units to be mixed quite effectively. Since all of their contemporary strobe units utilize this system, they can ALL be mixed while achieving predictable results. In fact, ALL strobe systems (regardless of brand designation) can be mixed with predictable results, as long as they all utilize this scaled designation.