New LED replacement bulbs that fit mole tweeines?
Posted 29 March 2015 - 02:54 PM
1. Has anyone ever tried this? And what were the results?
2. Am I just crazy and this would never work for reasons I am not taking enough time to consider?
Posted 29 March 2015 - 02:58 PM
Posted 29 March 2015 - 06:55 PM
I wonder if there's any way to dim them?
Posted 29 March 2015 - 07:19 PM
Had this idea with a friend years ago who knew a company who could make it-- though the fool, of course never went through with it.
Posted 29 March 2015 - 09:45 PM
seems like a great idea - I'm thinking they ad a little chip in the bulbs and get an Iphone app going for dimming and possible color temp adjustments
Posted 30 March 2015 - 12:32 AM
Eh I see no reason for apps; just make it so you can throw it on a variac; though dunno how realistic that is.
Posted 30 March 2015 - 09:18 AM
I hear ya ....the new tech always leads to problems ...but it is the future as they say.
Posted 30 March 2015 - 10:30 AM
Suspect they may not like variacs. The modus operandi for that sort of thing is invariably a current-regulating power supply, so that if you reduce the mains voltage going in, it'll simply draw more current and maintain the same overall wattage.
That said, it's generally fairly straightforward to make that sort of thing dimmable, by modifying the feedback loop in the power supply electronics.
That really is a very interesting little object, I'll have to see if I can get hold of one. The concern, naturally, will be colour rendering, as well as output. 1kW of tungsten is a lot, and an LED would need to be 200-250W to equal it. That's a lot - a lot - of cooling problems in a package that size. Still, even if it isn't quite a thousand-watt equivalent, and even if it doesn't quite have perfect colorimetry, it may still be quite useful.
Posted 31 March 2015 - 08:01 PM
Did you look at the thing? Did you not see the muffin fan? After you fire it up, how long before the sound guy kicks your ass off the set?
Posted 31 March 2015 - 10:24 PM
Posted 01 April 2015 - 07:15 AM
Heat sinks don't make noise, motors and moving air makes noise. "Quiet on the set!", means just that. No need to be P.C. about it.
Posted 01 April 2015 - 04:32 PM
Posted 07 April 2015 - 08:16 AM
Plus, it's directional, not omni-directional. So it won't play at all with the reflector. You'll get light out of it, but as a small spot in the middle of the fresnel at all focus settings.
Posted 14 April 2015 - 09:39 PM
You'll get light out of it, but as a small spot in the middle of the fresnel at all focus settings.
Not exactly, the reflector has nothing to do with filling the back side of the Fresnel lens. It is a common misunderstanding is that the reflector collimates the light of a Fresnel head. In fact, the purpose of the reflector is to double the intensity of its' output. When the light-emitting filament of the bulb is placed near the center of curvature of a spherical, concave polished mirror reflector, the reflecting surface creates an image of the filament. That image is located in the same plane, but slightly displaced from the filament itself. This has the effect of doubling the amount of light forward projected from the locale of the lamp filament.
In other words, without the reflector, "this reflector light" (the dashed lines in the illustration above) would have been lost in the back of the lamp housing. With a reflector, these rays of light are collected and sent back to their point of origin where they emanate forward, parallel with the direct rays of light from the filament (the solid line in the illustration above), towards the back of the Fresnel lens where they are together collimated by the lens (for this reason the filaments of the bulbs used in Fresnel heads are designed with an open geometry to minimize blocking of the retro-reflected light - making them not quite an ideal point source.) Now that all the light that emanated forward and back, emanates forward from a single point within the fixture (the filament and its mirror image), the light projected forward is doubled. Quantum dot LED fixtures like the one being discussed here do not benefit by this light doubling action which is why they tend to be weak by comparison to traditional tungsten Fresnels.
Use this link for other features of traditional quartz Fresnels that LED Fresnels have not been able to duplicate.
Guy Holt, Gaffer
ScreenLight & Grip
Lighting Equipment Rental and Sales in Boston
Posted 15 May 2015 - 09:08 PM
There is no way these led could put out 1000w or 500w equivalent. There is a reason why all current LED Fresnel are so much heavy and larger compared to tungsten Fresnel. Start doing the photo-metrics calculations and see all companies exaggerate there output equivalent to tungsten or HMI. Its a heat and noise issue with COB leds. After working on my DIY led conversion project, I had to research on trying to keep the heat down and noise level. You need a much larger fan to move enough air and keep the noise down. These fans look tiny. Comes down to it Led COB (chip on board) are just not heat efficient enough yet to truly replace a tungsten bulb. Don't get me young I believe in the LED technology and there is hope, there has been a bunch of break though research done over the last year alone that could double the light out put and cut the heat in half. So until then I've put on hold to investing in Led as a tungsten or HMI replacement.