Compact Flos

[Paul Bruening]

How does a compact flo produce 100-120 watts of tungsten equivalent light output and only require 24 watts to operate?

 

http://www.fullspectrumsolutions.com/24w_p...act_65_prd1.htm

 

If this is the case, why not make an array of 10 X 10 lamps to get a 12K that only draws around 3K?

[John-Erling Holmenes Fredriksen]

You mean like a 2,5k HMI?

[John-Erling Holmenes Fredriksen]

When the manufacturers try to give you an idea of how much light output a light will give, they usually compare it to the output of an incandescent. What it means is not that your Compact Flo will magically make 75 watts appear out of thin air, it just means that it outputs the same amount of light as a 100-120 watts incandescent bulb. It just means that the Compact Flo is an efficient light, using less power to give more light. This has been common for a long time, and fluo's are generally power efficient lights. So are HMI's. An HMI is generally considered to produce 4 times the amount of light, compared to a same-sized tungsten lamp. So a 2,5k HMI fresnel will be roughly 4 times stronger than a 2,5k tungsten fresnel, and have an output closer to a 10k tungsten fresnel.

 

Someone please correct me if I'm not completely accurate on some of these points, I'm not an electrician :)

[Paul Bruening]

I don't recall casting doubt on HMI's.

[Paul Bruening]

http://extranet.mole.com/public/index.cgi?...07&id=11999

http://extranet.mole.com/public/index.cgi?...em&id=12041

 

Cost of 12K (3000W) Compact flo DIY light? I'm guessing around $900.00 depending on how handy a person is with metal and wiring. Of course, I don't know if it would melt the plastic ballast covers on the lamps or anything like that. They recommend not putting them in enclosed lamp houses. So, I'm thinking their guts are heat sensitive. It would be a broad only, as well.

 

I'm just musing.

[Richard Andrewski]

If all you care about is a big broad source and you would tend to put diffusion on your tungsten or HMI's to turn them from hard lights to soft lights then I suppose you may be happy with the results. But if you expect a one to one then you'd be disappointed.

 

The hard light of undiffused tungsten or HMI will have more throw than your broad 3K flo panel. Shadows would be cast differently. You can use a hard light for projection of cookies but never could with your 3K panel.

 

What you'll have is really something more like a homemade Fisher light or huge softbox and would most appropriately be used in the places where you'd use such a light like for car photography / video / film use.

 

You just can't turn a fluorescent bulb into a hard source no matter what you do and it would never be suitable for use in a fresnel or have a lot of throw. HMI is the king of energy efficient hard light and you can get the 4 to 1 leverage there too like you can with fluorescents--also remembering though that HMI fixtures get very hot but the light output is cool like fluorescent without all the infrared that comes from a tungsten light.

 

And yes, the guts are heat sensitive so you'd want to pay attention to natural ventilation and not restricting air flow if you want to keep the bulbs going for a long time.

Edited September 11, 2008 by Richard Andrewski

[Paul Bruening]

I still kinda' like the idea of a cheap, 5900K, 6KW broad for interiors that I can simply plug into a wall socket and not even overload the cheapest 15Amp rated socket. I, generally, hate the light from flos. But the light value to energy demand ratio is rather convenient, I must admit.

 

What's the flicker concerns on those things?

[John Sprung]

Actually there were some guys at HD Expo last time who had a setup like that for sale. They had a source for really humungous CFL's, equivalent to 500 or 1000 watt incandescents, IIRC. The CFL's were about $50 each. CFL's operate at high frequencies, so flicker isn't an issue unless you need to do extreme slow motion.

 

On the horizon is Luxim's LIFI technology, which can more than double the lumens per watt you get from CFL, with better color. They have a notch, but no spikes in their spectrum.

 

 

 

 

 

-- J.S.

[Paul Bruening]

Hey John,

 

The guys in the link above were selling those for $10.00 each on large enough orders. I can't account for if they're any good or not. Do you know those guys source for 500 and 1000 watt units? $50.00 sounds cheaper than a pile of smaller lamps.

 

The new technology you mentioned sounds interesting. Please, keep us informed.

[Richard Andrewski]

Flicker is less and less of a concern these days with electronic ballasts in general. I have seen some small CFLs flicker before but you have to remember that the ballasts in the base of those things are super tiny. When you get a separate ballasted light you get a full electronic ballast with all the necessary (not abbreviated) circuitry for driving at a high frequency and most of all giving a good power factor which is the spec on ballasts which tells you how much they meet their theoretical output in real life. .98 is a common spec which means they drive at about 98% of their theoretical power and that's considered great.

 

A 200w CFL is about the largest with some rare exceptions that you will find around the market. Assuming a good power factor in its ballast it would put out about the equivalent of 700w worth of light--comparing to tungsten behind diffusion. That bulb is normally in an "8U" configuration which means that there are 8 flo tube "U"s attached to the ballast in its base and it will normally also use a mogul (E39 or E40) base so you need to use a larger socket. Lastly, while you might get away with it, I wouldn't use plastic sockets. Go for ceramic, you'll have greater peace of mind.

[Paul Bruening]

Any leads on sources for big CFLs?

[Paul Bruening]

http://www.farmtek.com/farm/supplies/prod1...995_103999.html

 

These are cheaper per watt than the 200W units. Just from the look of them, I'm guessing you could line them up in a row at about 12 and have a fixture roughly 3 feet wide by 1.5 feet tall and about 6 inches deep. It would kick out 6KW at a CRI of 93 and plug into a wall socket with no troubles. Clip a sheet of frost in front and you've got a broad to fill softly in window lit interiors. All for around $650.00 in lamps and parts. I'm glad to hear that the flicker isn't a problem. Another benefit is that you can put the smaller CFLs into the scene lamps and be color groovy all the way through the shot: scene lamps, high KW fill lamps and windows without the hassle of gelling or lens filtering. At about 24 lbs. they wouldn't need monster stands. None of that ballast hassle. No sunburned cast and a lot less heat.

 

I like.

[John Sprung]

Another interesting advantage to ganging a dozen CFL's -- They each have their own high frequency ballasts, so they'd be completely randomly phased. That would fill in and reduce flicker even at extremely high frame rates.

 

 

 

 

-- J.S.