Using household fluorescent lights

[Birkkromann]

Hi,

Does anybody have any experience using standard T8 fluorescent bulbs for lighting?
I know Kino Flos would definitely be the best solution, but I don't really have that much money to spend.
Anyway, I was just wondering what the disadvantage would be when using T8 bulbs fitted to a normal household fluorescent fitting.

Thanks
Birk

 

[Moseph]

Household fixtures aren't made for motion picture use. No barn doors, no control grids, and being less durable are your main disadvantages. Some of them come with electronic ballasts which won't flicker, but some have magnetic ballasts which will cause issues when the camera isn't on specific shutter / framerate settings. Kino Flo does make T8 lamps, which solve the green spike inherent in so many cheaper fluorescent lamps (within the context of other Kino Flos, of course it's not as good as real tungsten or daylight).

 

[Richard Crowley]

What do YOU mean by "standard T8 fluorescent bulbs"?
The range of available tubes runs the gammut from horrible green-spike home-warehouse budget specials to products with CRI up past the 90% range.

And, as Mr. Moseph observed, you can have a CRI of 100 but if you are using an old magnetic ballast, you are screwed by power mains frequency strobing.

And certainly it is true that it takes more to DIY something as usable and flexible as KinoFlo products (and similar commercial units). But OTOH, in many applications (expecially fixed installations, you not only don't need those kind of features, but sometimes they actually get in the way and are a waste of $$$.

Take a look at this before jumping to any conclusions, however...
http://www.dvxuser.com/V6/showthread.php?294003-DIY-Kino-Flo-4-light-set

There is noting magic about KinoFlo (except for the phosphor formulation of their tubes). You can put KinoFlo tubes into conventional fixtures and they will put out the same beautiful light without the $500 fixture behind them.

 

[Michael Carter]

There is noting magic about KinoFlo (except for the phosphor formulation of their tubes). You can put KinoFlo tubes into conventional fixtures and they will put out the same beautiful light without the $500 fixture behind them.

But aren't Kinos (and many knockoffs) using overdriven ballasts to boost output? That's my understanding anyway, and my personal experience trying to DIY flo's. May not make a color difference, but output's significantly hotter with an overdriven ballast.

 

[Moseph]

But aren't Kinos (and many knockoffs) using overdriven ballasts to boost output? That's my understanding anyway, and my personal experience trying to DIY flo's. May not make a color difference, but output's significantly hotter with an overdriven ballast.

I've read this many times on here before, I don't think it's as simple as the ballast overdriving the lamps. Kino Flo 4' T12 lamps are 75w, while most others are around 40w. I believe the ballasts are only "overdriving" them in the sense that they're meant for use with their own higher output 75w lamps. So if you use them in a shop or household fixture, you're almost certainly underdriving them. But I think (though I could be wrong) that if you were to get a ballast like this that you'd have the same or very similar results to a Kino flo ballast.

If I were building something, I'd go with T8's though. They're more efficient than T12's.

 

[Movie Mike]

There is noting magic about KinoFlo (except for the phosphor formulation of their tubes). You can put KinoFlo tubes into conventional fixtures and they will put out the same beautiful light without the $500 fixture behind them.

To get as much output as possible, Kino Flo ballasts drive their tubes at a higher output current (800mA) than standard high frequency electronic fluorescent ballasts. The phosphors in Kino Flo True Match Lamps have been formulated to match the spectral sensitivity curves of film and digital imaging equipment at the higher milliamps at which the ballasts operate. For this reason Kino Flo True Match lamps should be used in Kino Flo fixtures only. The tubes to use in standard electronic ballasts are the Movie Tone tubes.

When it comes to lighting equipment, you generally get what you pay for. Lighting gear is so specific to the requirements of our industry that it is hard to build your own. Fluorescent lights are a good example in more ways than one. Besides the color issue, Kinos also use high frequency ballasts to eliminate flicker or scrolling. You can get cheap high frequency fluorescent ballasts from a residential lighting supplier but they can have another type of flicker problem called an “eratz ripple. If that weren’t enough to justify the price of Kino fixtures, the newer Kino Flo fixtures that use the biax tubes use ballasts that include Power Factor Correction (PFC) circuitry. As it does in HMI ballasts, this advanced electronics contributes to a more economical use of power than conventional electronic ballasts.

A fourth magical ingredient to Kino Flo ballasts pertains to the newer Biax fixtures (Diva, Parabeam, Vistabeam, Barfly) and is probably the most difficult to understand because it has to do with the Harmonic currents that DIY ballasts will kick back into the power stream that the ballasts of these Kino Flos don’t. According to this thread the Harmonic noise generated by DIY ballasts can damage HD digital cinema production equipment, create ground loops, and possibly create radio frequency (RF) interference. In other words, saving a few bucks by building your own lights can cost you a considerable amount of money in lost time or damaged equipment. For a detailed explanation for why this is, see http://www.dvxuser.com/V6/showthread.php?198578-Use-industrial-fluorescent-banks-instead-of-Kino


Movie Mike

 

[j1clark@ucsd.edu]

When it comes to lighting equipment, you generally get what you pay for. Lighting gear is so specific to the requirements of our industry that it is hard to build your own. Fluorescent lights are a good example in more ways than one.

Movie Mike

I don't disagree that there is a 'reason' to pay more for... more... the problem which I think the OP is facing is it is not a choice of 'gosh I have $1K bux in my pocket so why should I buy a Kino-flo when I can 'assemble' my own'... but the situation is 'I got bupkus in my pocket... and need something that will 'just do''...

I'm in the same boat as the OP... the Wife gets to spend money like water... I don't...

For issues like CRI, 'green spike', etc... My personal recommendation is to shoot with Monochrome output in mind... then, while there are still some issues relative to color response and the spectrum of light, such issues as 'color cast' disappear, and perhaps some issues such as 'red' (popular in living human tissue...) not having equal weight with the dominant 'green' spike, but with a bit of adjustment that can be mitigated...

The only remaining issue is the issue of varying light depending on the type of ballast... for the most part...

And what's more... with going B&W one learns how to actually light a scene... but perhaps I'm showing my prejudices on the subject...

 

[Dthornotn]

Your statement "with going B&W one learns how to actually light a scene" pricked my interest. I am trying to learn how to light a scene, how would this help?

 

[tom_wise]

Your statement "with going B&W one learns how to actually light a scene" pricked my interest. I am trying to learn how to light a scene, how would this help?

What he is speaking to is eliminating a variable. By taking out one of the problematic issues, The shooter then deals with one less issue. In other words, shoot B&W and forget about color spikes and color casts. Simplified but fairly accurate.

 

[starcentral]

Hi,

Does anybody have any experience using standard T8 fluorescent bulbs for lighting?
I know Kino Flos would definitely be the best solution, but I don't really have that much money to spend.
Anyway, I was just wondering what the disadvantage would be when using T8 bulbs fitted to a normal household fluorescent fitting.

Thanks
Birk

Rather than speculate its best to test, try it yourself, and more specifically try it in the exact purpose you intend to use it in. ie. will they be hidden gelled accent lights - or providing key light on a subject?

Sure you will need to flag / control those bulbs somehow but since they are relatively cool you can find a million ways to do so. Also if you plan on grading your film then I feel high CRI quality is over-rated. You can get away with high 80's to low 90's, or much worse and still be fine depending on what look you're going after. There are two sides to every equation.

I've been using Alzo's flo 4-bank and 2-bank lights which you can buy between $250-$399 and they work pretty well except they are only 2 feet in length.

Here's an excerpt where from 0:00 - 0:56 I'm using an Alzo 4-bank mixed with ambient practical lights, and from 0:55 - 2:01 I'm only using the CFL's that were already in the room in the corner.

http://www.youtu.be/4qHHWz2NNRo?hd=1

Now you may not like my greenish-puke-tint grading job on the video (as has been mentioned by several people on the completed video) but I bumped out mid-tones from the red channel and trust me there was lots there to keep the images warm if that it something I would have wanted.