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p.4 #6 · Houston, The Einstein has landed | |
bacilonur wrote:
Definitely doesn't cover the whole thing, you can see Ellis' closet doors between the body and the dome in his shot. That's probably for cooling purposes, the same way Profoto puts holes in their domes. I don't think it'll make a difference in the quality of the forward-projected light, but there will likely be a 360º hotspot when shooting barebulb without a reflector.
I personally did all the mechanical and electronics design for Einstein. Only the programming was done by consultants.
The cooling design is very thorough. All cooling paths are equal to or greater than the surface area of the fan. This includes the space between the dome and the back plate. Dome cooling is provided by Venturi effect . . the air enters the dome via radial slots in the back panel and the geometry causes the air to flow around the inner surface of the dome and out the space between dome and back plate, cooling the dome and lamps efficiently. The dome, flashtube and modeling lamp are all Pyrex, and the flashtube and modeling lamp get much hotter than the dome.
Heat expansion of a rigidly mounted part is always a concern. Perforating the dome does not prevent cracking potential caused by heat expansion, but allows spots of light to escape and reduce the diffusion effect of the dome. To this end, the dome is held in place by spring clips that allow for thermal expansion with no stress on the dome. Same for mechanical shock to the dome. It is easily replaced and inexpensive if a failure ever occurs.
We have done extreme duty testing and have never seen any deterioration of the dome and are confident in its integrity and can say it is extremely effective in diffusing the light and protecting the lamps. It has no measurable light reduction and also serves to add UV reduction to the already UV coated flashtube. It also serves to satisfy international regulations to provide a glass safety shield over quartz halogen modeling lamps . . . . a requirement not satisfied by most flash units that feature an exposed quartz modeling lamp.
Edited on Apr 09, 2010 at 05:12 PM · View previous versions
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