mmurph Offline Upload & Sell: On
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p.1 #17 · Ranger vs AcuteB: power??? | |
Yeah, Simon, I mostly agree.
But this discussion has been bubbling for a couple of months here with a lot of messy and inaccurate information and conclusions.
They finally tricked me into doing the testing myself in a way tthat neutralizes the effect of the different reflectors.
In other discussions, some folks did not realize the difference in relative output for a Magnum reflector over a wide angle reflector, for example. They have tried to compare those 2 numbers directky.
Profoto has a really nice - but complicated - chart indicating the f stop output (rating) for all of their reflectors on the same heads at various Ws ratings. Can't find that right now though.
Funny, I actually did forget to include the UV protecting glass on the Broncolor head that I used in the test. That probably accounts for my .3 stops difference!!
The Visatec uses a clear protecting glass for their tube, as they are only 300 Ws. The Broncolor uses a UV coated protecting glass for the 3200 Ws tubes. The ntubes run too hot at that power level to coat the tube directly.
Looks like Bron already compensates for the glass in their Ws rating calculations.
I suppose I could rerun the tests to verify that. I also should run them at 2 meters so that we can compare directly to the manufacturers specs, which are quoted at 2 meters,
(It looks like converting my 10 foot measurement to 2 meters would require us to add about 1 and .7 stops. So the Topas, at 400Ws at 2 meters, with the SB, would be about f/ 16.0 The Visatec at 300 Ws at 2 meters would be about f/ 11.0 +.2
That sounds about right. The Profoto rating for the Acute 1200 with a Zoom reflector at 2 meters is f/ 45. The Topas at 800 Ws, at 2 meters with the SB, would be an f/ 32. That would be f /45 at 1600 Ws.Bron rates it at f/ 45 +.7 at 2 meters with 1600 Ws and their standard P70 reflector, or a loss of .7 for the SB.. )
OK, enough technical BS. I want to think about making images!! Totally different use for the brain.
As I said in the last thread on this, I went 25 years without ever caring about these number comparisons!
Best,
Michaewl
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