Paul Buff
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shoebox9 wrote:
Wow, Paul's post above killed this thread cold for over a day.
Here's my read-
* This is potentially good for some people buying PLMs to use with Elinchrom RX/BX/Ranger/Quadra/etc, because Elinchrom strobes have a curved back plate to focus more light forward. This creates a hotter centre than the PCB strobes that the PLM's were designed for. PLM's with a manufacturing flaw that causes a 3/10 f darker centre with PCB strobes, may actually be more ideal for Elinchrom users seeking a smooth even light.
* Those using PCB strobes with the PLM reflector, and the silver or white PLM's WITHOUT the front diffusers, are uneffected.
* People using PCB strobes who also bought the front white diffusers, are worst off, because trying to move the strobe 4" back with the front diffuser in place, presumably won't work.
Sorry - wrong on every count - no offense.
The slightly dark center is not a function of the angle emitted by the flash and it's sub reflector - it's a function of the angle of the PLM fabric relative to the distance from the source. So I wouldn't expect any change in the pattern from an Elinchrom VS a bare bulb. You'll have less light at the edges of the PLM fabric. but the projected pattern should be approximately the same.
This also applies to using the PLM reflector VS bare bulb (AB/WL have a flat back plate, so the angle of emission is about 210° VS about 170° with the 7" PLM reflector.)
The position of the source, when using the white front diffuser has no dark center. The physics are entirely different and the beam is very wide with no anomalies.
Though a slight technical flaw, it shouldn't cause any significant problems in actual use - just position the flashtube slightly forward of the umbrella edge. The 7" PLM will still block any side spill. I am refining the umbrella curve as we speak, but it will be probably three months before any changes show up on production units.
It's very hard to translate a CAD design to fabric and bent rods. It's also difficult because of the segmented shape - it becomes a calculate - build - test deal. Then you have to hope the vendor exactly repeats the fabric shape, sewing and stretch factor between sample and production. Believe me, trying to control and communicate all this to a Chinese vendor is especially difficult.
I'l love to build this in America but there simply aren't any umbrella factories left and the cost would triple. To try to build it in our factory would involve setting up sewing machines and hiring a very-difficult-to-find product engineer/supervisor and non-existent US sewing workers.
As a note, I believe every test shot published here is positioned such that it has a broad center darkening of about 3/10f . . . this is pretty hard to see in typical shots and is likely discernible to the eye only when shooting against a flat wall or seamless.
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