Where to get high frequency flourescent ballast? (DIY Home made Kino Flo question)
 

I've been reading up on home made kino flo's and have found the following resources:

http://www.dvinfo.net/conf/showthread.php?t=50192o
http://www.dvinfo.net/conf/showthread.php?t=9751
http://www.dvinfo.net/conf/showthread.php?t=45182
http://www.dvinfo.net/conf/showthread.php?t=12671
http://www.studio1productions.com/Ar.../FL-Lights.htm

One thing I have yet to find though is where to purchase 25kHz or higher output electronic ballasts. I went to my local electronic supply store and they called their supplier, Sylvania, who said they have nothing of the sort. I know the ballasts must exist as

A) people mention having them on this forum in the above threads
b) when I do a google search for them I find chinese manufactuers listing them for sale.

Does anyone know a retailer which carrys affordable (under $100) high frequency ballasts?

yes, but I'll do you one better. Little secret called ahsupply.com
They sell kits WITH AMAZING REFLECTORS for 2 bulb setups, about 65 with everything but an enclosure and bulb. All wiring, caps, etc included, and I think they run at 60 khz. ot 60hz, 60 KHZ. I use them for video, stills, you name it. With their reflectors they are simply amazing! About 2x the output of a kino diva 2 bank. But, if you really want a completely DIY solution, the ballast they use is a Fulham Workhorse 5. Good for about 120 watts in any bulb configuration. Google "Fulham workhorse" and you'll find that most commercial lighting suppliers will sell you their ballasts for about $30 or something (to drive 2x55w bulbs). I thought long and hard, and ended up with AH supply, because their reflectors are better than anything I've ever seen before (arri, kino included) and would cost WAY too much to buy separately or make. They are very very very very efficient. Comparable in output more to kino's parabeam series. Work to the wise - use good bulbs! Osram studio's or Kino's. You'll kick yourself later trying to get away with $9 bulbs when for $23 you can have the right bulbs and not need filtration or frustration. To your eye, they may even look the wrong color, but on film, they record perfectly. Hope that helps!

Model number for the ballast you mentioned is WH5-120-L - The spec page is here:
http://www.fulham.com/Detail_Ballasts.php?ID=WH5-120-L
EDIT: It looks like all electronic ballasts have high enough output frequencys

An article I found says all electronic ballast runs at more than 20khz - can anyone with more of an electrical engineering background verify this?

Yes,
electronic ballasts run at around 20KHz. The supply of course is 50/60Hz going into them.
The average electrical supplier would not understand this, just tell them you want an electronic ballast.

BTW Osram make a full range of ballasts to suit their Studioline tubes. They're also available with dimming control via 0-10V input.

According to the studioline webpage (http://www.sylvania.com/BusinessProd.../DisplayOptic/ ) it looks like they use standard Sylvania QUICKTRONIC electronic ballasts.

OSRAM STUDIOLINE®
Compact specialty fluorescent lamps with special phosphor coatings designed for TV studio, cinematography, and photographic applications. STUDIOLINE lamps are suitable for 120V or 277V applications and can be dimmed to one percent of light output with QUICKTRONIC ballasts

yeah, the wall power is 60hz (usa) but the output (operating) frequency of the workhorse is 60 KHZ. It is twice the recycle of the standard electronic ballas - I talked to them on the phone a while back.

One thing to note - Kino's over-drive their tubes, so SOMETIMES (and I'm not positive which fixtures) they compensate in the phosphors of the tube to make up for the fact that they overdrive (i.e. adding more magenta). Not positive which tubes though. I have Osram daylight tubes and they register 5500k with no green spike.

oh one other thing - I've found that dimming the bi-tube lamps makes them color shift VERY badly. Kino's, Moles, Arris, they all do it when dimmed. It's a feature of the lamps. ND is a much more predictable way to dim (or back them off) bitube fixtures. Straight tubes don't do this, so if you're making a fixture for t12 type lamps, should not be a problem using dimming ballasts. Be forewarned though.

Also, ballasts meant for t8 tubes will overdrive t12 tubes. Even if it is electronic, it must be auto-adjusting in order to drive it correctly on a different sized-tube. Not all electronic ballasts are auto-adjusting. The workhorse ballasts are auto-adjusting. I know it's bizarre logic, but wider tubes take less power to drive. They have less light output but they also take less voltage. That said, it is possible that Kino uses electronic t8 ballasts to drive their t12 tubes, achieving their "overdrive." Just a theory.

Must say I've never noticed a color shift dimming single D tubes run off electronic ballasts, not once the tubes are warmed up. That can take a few minutes at full power and a lot longer if they're dimmed.

I agree about Kino overdriving their tubes, they seem to run pretty hot and not last anywhere near as long as regular tubes.

Yeah Bob, they do take a LONG while to warm up, but even after that, all 2g11 lamps shift pretty badly when dimmed. I asked a few othe people about it too, and it has to do a lot with the diameter of the tube. Film-safe lamps don't eliminate the green spike, they correct for it. In the phosphors of the tube they add magenta so you don't have to gel magenta later. Problem is, when you dim a tub of this size, the temperature of the mercury arc drops significantly and outputs a lot less green - hence a color shift. When it's fully warmed and fully powered, the phosphors are matched to the exact spectrum of the arc. On wider tubes, there is less of a temperature difference between fully on and dimmed, so much (if at all) less noticeable shift.

All that said, if the tubes are brand new, it will matter a lot less than tubes with a few thousand hours.

Are there over-the-counter compact fluorescents which are suitable for video? While I was at the electronics store I asked if they used electronic ballasts and told they do, which means there shouldn't be an issue with flickering. They also appeared to have CFLs in the suitable Lumen range, although none had their CRI listed on the package.

Then again I haven't even checked the price of the CFL they sell at photo stores, so maybe it isn't even worth it for the minimal cost savings

Yes and No. It all depends on how much gellin' you want to do. Video has a much easier time balancing the spikes of fluorescent lamps than film does. Kino's were invented for film. You can certainly get creative and use over the counter lamps and gel your other lights +CTG (not sure what percentage, all depends on the lamps you choose) to match, and take a white balance reading. The camera will effectively balance out the green spike. To be completely honest though, these lamps have VERY long lifespans compared to tungsten, and even the kino's are comparable in price to tungsten globes. For an arri, you'll spend about $20 for a lamp in a 650 fresnel. For a kino lamp you'll spend about the same. The difference is that corrected fluorescents last 10's of thousands of hours (if treated well). My personal choice was to spend the extra cash and save the headaches later with gelling all other lights (or the flo's and losing power). Plus I use them mixed with my strobes for still photography, and I know they match when I use Osram daylights.

Jaron - Great Tip!
 

Hi Jaron:

I have been working on a homemade Kino fixture, which I will show all of you guys in a few weeks when I can get a spare few hours to finish it. However, your link to AH Supply blew my mind, their kits seem like such a deal and I like the idea of the MIRO reflector. What are you doing for eggcrate and diffusion for your AH lights?

I am ordering the 2x55 kit tomorrow, seems like it fits the bill. At $64.99 ea. plus about another $42.00 for each set of Kino 5500 tubes, seems like I have a Diva 200 for about 1/8th of the cost. High frequency ballast, same output with the good CRI, etc.

Brilliant find, thanks for the tip!

Dan

Jason - what do you use for enclosures / mounting mechanisms?

Well, I don't live far from Chinatown / the restaurant district. I found a place that does custom stainless mfg cheap and well, so I have this guy build me pans and yokes. I bring them home and drill / pop-rivet the pieces together. REALLY durable. Actually they are fairly light weight too, believe it or not. I'm trying to figure out a new way, so I'll keep you posted. In the meantime, this works well, and they can really take a beating (unlike kinos).

For me, the enclosure/mounting mechanisms are the "weak link" left in DIY lights - all the stands, electronics & wiring, bulbs, & reflectors are easy to source super cheap .

no joke. If you come up with something great, please share. Until I figure it out, I'm pretty happy with the stainless enclosures. Not perfect but they work.

I've contacted some chinese manufactuers about just this question - Basically, If I can gather 1000 orders, I can get whatever I want custom machined by them.

Another option is get someone with mechanical engineering knowledge to get some CAD drawings made up, and have them CNC machines by emachineshop.com or another local machinist.

A final option is to import some Savage brand lights from China - http://www.savagepaper.com/lights.htm (Minimum order: 50 units), and modifing them to use T8 Tubes.

Well, I happen to have been an ME in a former life. I actually have sketches of the enclosure I will be building, but I don't have a PC, so until I leap that hurdle I can't use emachinshop. Once I DO get a final file done for them, I'll post here to see if anyone else wants the parts. Easier to order in bulk... but either way I will put the files online so anyone can order should they choose.

But... I may have another solution entirely...I'm going to chinatown on monday to investigate so I'll get back about it then. could be good...and relatively inexpensive.

Jaron, Ari,
What would you recommend for stands?
Vic
P.S. It looks like I'll be ordering AH supply soon; thanks for the info guys.

I got this URL from Victor Milt's website

http://www.bulbs.com

They have 5000K CF's for cheap.

Jason? Mounting issues?
 

Hi Jason:

I ordered the AHSupply 2x55 watt kits and they have arrived. So far, I am thinking of mounting the reflectors onto a piece of 1/2" birch plywood, then using a Matthews baby plate for a 5/8" spud to put into a regular grip knuckle on a C-stand?

Have you been able to come up with a better solution? I think that my solution will work but I bet you have something a bit more elegant worked up?

Pictures, links or descriptions? I like the yoke that Kino uses on the Divas but not sure where I can source it from. I suppose I could just buy them from Kino but I am not sure how they attach them to the Divas, Pop rivets, screws or ??

I will have to drive over to Film Tools and take a look.

Best,

Dan

Somewhat more elegant, much more expensive though. In chinatown, i have a guy weld me stainless steel open-top boxes 23"x18"x2.5" (4x55 watt kits). I bolt

http://www.bhphotovideo.com/bnh/cont...ughType=search

onto the back using 1/4"-20 hardware, and the ballasts are pop-riveted to either side right along the centerline. it's a squeeze, but it JUST fits. The steel is 18ga and all the seams are tig welded. Really nice, super durable and actually pretty light. I ended up soldering and shrink-tubing all the wires, just to be 100% bulletproof, and it really cleans up the inside.
I'll try and snap some pics this week.

Oh, and for 2x55's, the box is 23"x9"x2.5"

Nice!
 

Hi Jason:

Wow, nice find on that Avenger baby plate!

Sounds as if you have some bucks tied up in your fixtures but they sound very well made. Would love to see some pictures.

Are you using anything for barndoors, diffusion or egg crate?

Dan

Coroplast thickness on Divas?
 

Hi all:

I am working on these Jason lights (I think we should refer to AHSupply lighting kits as 'Jason lights' since we would not have known about them without Jason's help) and I am hoping to use Coroplast, the same type of black corrugated plastic sheeting that Kino Flo uses on the Divas.

Does anyone have an idea of how thick the Coroplast sheeting is on the Divas? I can source it in 2.6mm, 4mm and 6mm thicknesses but I would rather not drive across town to look at a Diva in person to determine how thick the Coroplast is that they use.

I am thinking of Coroplast as a main body shell but still using the Miro reflectors that came with the kit. I don't anticipate the light folding up like a Diva does because there would not be room with the Miro reflectors but I think having the additional throw from the tubes will be worth it. The Coroplast would serve as the body for the lights as well as the mounting bracket and the ballast.

Thoughts on this design idea?

Dan

Just a minor question...
Why do you keep calling Jaron 'Jason'?

Here are some alternative light stands I've seen at GuitarCenter.
http://www.guitarcenter.com/shop/dj_...tand&x=14&y=12

The American DJ LTS-1 Light Stand supports up to 100 pounds. I've seen that one at the local store and it's pretty stout.

Looks like you could make brackets similar to the Lowel Flou-Tek studio flourescents for it.

haha, good catch Joe. It's an unusual name.

I chose not to use that plastic because, while it is successful on a number of lights (incl. mole's biax series), I think I'm less than gentle sometimes, and I have broken kinos. The shells get worn easily - hence the reason they sell replacement shells. The problem with using that material, is that you still need to make it rigid enough to support the light and accessories. Mole uses stamped steel end caps and really clever accessory holders riveted to the plastic, but they use thick metal backer-plates so the rivets don't tear out of the plastic. When I weighed it all out, it was lighter and stronger to just use a steel box. The miro reflectors are only 2" tall, so in a box 2.5" deep, it all fits neatly inside. Now, that plastic makes a GREAT barndoor, and mole does exactly that on the biax. I haven't yet ordered barndoors, but I think I'll just buy Lowell's caselite doors and rivet the hinges to my fixtures. They are cheaper than anything I could build.

Someone mentioned that I have a bit of cash tied up in these. yes, it's true. From the outset, I knew it wouldn't be cheap to make them right. But, I think what I have is more comparable to the parabeam than the diva. Sure, the AH ballasts don't dim, but I mentioned a while ago - i've never been happy with how the 2g11 bulbs dim. Output-wise, they SPANK the lowell, kino, or mole fixtures, except the Kino Parabeams (which they're about equal to). If I compare the $200 it costs me to make a 4-tube fixture to the price of a parabeam...I smile. Sure, I spent 200, but it works well, looks right, and it'll survive a hurricane. Anybody here know how to post pics?

Question about output vs power used...
Normally when I buy FL for the home they state rated output ie 60w and power used..ie 15watts which is why they are popular. When I looked at the specs for the GE CinPlus it stated 55watt power, but no other figure. Do these light consume 55w or output 55w and consume less electricity than 55w?

55w biax lamps are 55 watts, as long as the ballast is driving them at the same current that is rated. kino ballasts over-drive their tubes, so technically they use 55w lamps but drive more power through them.

Lamps are rated by wattage, a measure of power. Strobes for photo are rated in joules (watt-seconds). Either way, it's a measure of power consumption. Light is measured in a number of ways, and lamps are commonly compared in foot-candles (candellas), lux, lumens etc. At home depot, they sometimes have compact fluorescents rated by "equivalent watts", or how much light a 13 watt flo will compare to a standard tungsten bulb. One thing to note is that ballasts and lamps themselves have differing efficiencies between designs and brands. Kino lamps have slightly less output than Osrams, and that's just comparing the physical lamps and not the fixtures. When it comes to lights, reflectors have a lot to do with the overall output, which is why the AH supply kit is so cool - the reflectors are extremely well designed, allowing them to, using the same lamps, project more light than Kino Diva's.

If you're comparing lights, use the actual light output as your comparison, not Watts. Watts come into play when figuring how many you can plug onto a circuit without popping the breaker.

As an interesting note, candellas are a very logical unit of light measurement. A foot-candle is the light made by one candle one foot from the measurement device. If you've ever seen Barry Lyndon, imagine literally calculating exposure by counting candles! I'm sure they used meters, but still, it would have been possible to get the exposure close by counting and measuring.

Reply
 

Hi Jose, I mean Joseph, I mean Joe:

I think I keep writing Jason because he seems more like a Jason than a Jaron.

No, actually because I type in a hurry and don't proof well enough. No offense Jaron?

Best,

Dan (or Don ;-)

They do mention lumens at both the GE and Sylvania/Osram sites, so I guess I can compare against lumens from HMI and Incandescants and figure out the power savings from there. My question had mostly to do with caclulating how much portable power would be needed to create 4 to 5K of light. Philips is using that as marketing for their new Ceramic discharge systems (250watt consumption, 1K output).

That's HappyJose to you!!!:-). My family calls me Jose, just don't tell anyone.

4-5K of what light? What style of fixture? If you're trying to create the same amount of light as a 5k tungsten fresnel at the beam center, it's a LOT different than trying to create the same output as a 5K softlight. That's why you can't really compare watts or equivalent watts, because they don't tell you what it's equivalent to. A 5k Hmi par will be brighter than a 5k fresnel par, yes, and a 220 watt fluorescent will be a lot brighter than a 220 watt tungsten softlight.

Tungsten lamps produce about 15 lumens/watt, whereas flo's produce about 80-100 lumens per watt. But you also have to factor in a lot of other things, like reflector design, size of the fixture, style of light, beam vs. field. In general, light output ratings that are advertised are center-beam readings. Tungsten lights usually produce more output at their center than fluorescent, due to the shape of the lamp itself. Flos generally make a pretty even beam all the way across (again, depending on the reflector), without hotspots. Flo's will almost always be "soft" lights. They will look different than softboxes and softlights, which is something to keep in mind if you're used to tungstend softlights. They won't provide the "punch" in the center of the beam that a tungsten will.

I know I didn't really answer your question, but it's because there's no consistent way to do it. My 4-bank flos (23"x18") are about the same output as my 2K chimera (24x32). They look VERY different, but if you're just comparing output, the flo is just slightly brighter.

Thanks, I understand the difference and intend to mix Flo (soft) and tungsten with everything at 3200K for indoor shooting. For tungsten, I'm looking at those 500 watt shop lights and replacing the bulbs with 3200k ones at the same wattage. I know there is a lot involved, so I have a lot of work cut out for me to get everything right. I'm looking at the GE CinPlus because they have 55w 3200K tungsten, with a CRI of 90+, which puts them closer to the actual tungsten halogen in color output. Thanks for the info on lumens per watt.

I'm also intrigued by those DidoLights for close spot work.
Also seeing if including some Briteks would be a better idea instead of the shop lights.

If the goal is flooding an area, shoplights will work fine. You'll need to flag them and figure a way to attach scrims if you need to do more than just flood at full power.

Dedos are amazing little lights, and they are great examples of lamps that defy standar notions of brightness per watt. They use extremely well designed and manufactured lenses and reflectors, so they definitely don't come cheap. The sharpest of their lights are the 12 volt heads. The actual size of the light "source" within is incredibly small compared to something like an arri, so if you want nice, extremely crisp shadows and cuts, nothing beats a Dedo.

Thanks again. I purchased a couple of 250watt shop lights at Home Depot, one of them came with a variety of attachment devices (clamp, spike, stand..).
One thing I can't seem to find is a 3200K 78mm Double Ended T3 type bulb.
There were several at 2700K.
Several options at 500watts, but nothing at 250 or smaller.

Anyone know of any place to check? (First place I went to was FilmTools).

Jaron, can you post pictures of you Flo kit? Just for reference?

Would scrims work the same way with Flourescents as tungsten?

Thanks in advance

Well, if someone could tell me how to post pics, I would be happy to put them up.

In terms of scrims, yes, they will work fine. ND gel will also work, because the lights never get hot enough to melt through.

Some time ago I did post in this forum some explanations on the 4-pin / 2G11 units I was using, adapting artifacts I found in local light fixture shops.

One of them was a chinese plastic unit, that I bought in Argentina, using one 36watt lamp. What I did was change the ballast, to use a 110/220v type instead of 220v only, and install an AC 3-pin socket. It's so light that you can gaffer tape it anywhere, like to a monopod I have. It has a plastic diffuse cover which can slide in or out to change light quality.

The other uses two 55W lamps, encased on a metal case designed to hang from the ceiling. It's much heavier than the other and it needs a tripod. It has separate switches for the lamps and a sanded glass diffuser. In fact it's the glass that makes this unit heavy, and a plastic diffuser should be more effective.

The color of any of these lamps can be easily balanced on-camera or corrected during editing. You can usually can pick 3000k or 5000K lamps, but what you should look for is the CRI number to be high. These are examples you can find at bulbs.com:

http://www.bulbs.com/products/produc...nventory=12610

http://www.bulbs.com/products/produc...nventory=11722

The first one costs $28.50, the second $8.00. CRI is 91 on first and 82 on second. CRI is an indicator on how linear/less spiky the unit is. The higher the number the more linear the lamp is, which is better for photography.

But high frequency lamps have a great advantage over 50/60Hz fluos, which is they don't flicker, so even the worst CRI types can be used if you correct the green a little with gells or celophane. Being cool running means you can use the latter too.

This all converts these lamps into very powerful, beautiful lighting tools, which we can DIY relatively easily.


Carlos