View Full Version : CFLs And Incandescent Bulbs Mixed In Array
December 21st, 2006, 03:41 PM
Here's a frame grab from a scene lighted by 3 compact flourescents:
Here's what I got after replacing one CFL with an incandescent bulb:
Postprocessing of the blue CFL frame in Virtualdub yields this:
- One can get a very good approximation of natural white light by mixing CFLs and Incandescent bulbs in an array in ratio 2:1.
- One can achieve the same effect with post processing, or possibly white balance (I'm yet to test white balancing since I used a digital still camera).
- Mixing the lights in an array post-capture should be superior to in-camera processing, which is superior to post-compression color processing.
- A mixed array of CFLs and incandescents close together mixes properly.
Has anyone else tried this? I'm building an array of light bulbs to use for lighting and because of this test I've decided to include 1 incandescent bulb for every 2 cfls in my array. And I think the results will be perfect!
December 21st, 2006, 04:19 PM
White balancing the camera to your lightsource is important. One can always correct in post, but I prefer to get everything correct in camera whenever possible. If you are going for a "look", often it is better to shoot neutral and then process the look into the piece in post. That way if something changes, you aren't hosed.
The thing to do would be to test how the CFL's compare to natural daylight and a tungsten light and see if they need any kind of filtration. It looks as if your test was at night, so if it's the only lightsource, correction is easy, just white balance. If you are using other lightsources, generally, they should all match each other. It looks as if the CFL's are a bit cyan.
I use Kino Flos a lot and their corresponding tubes integrate quite well with daylight and tungsten lights without filtration.
December 22nd, 2006, 01:27 PM
While I agree that white balance is the most important, I agree that there may be some merit to mixing CFL and regular incandescents. CFL don't have a perfect spectrum output but they are very efficient. If CFL and regular incandescent bulbs with similar color temperatures can be found, they might have nice color reproduction while increasing efficiency over just incandescents.
For your testing with CFLs, look for "soft white" or 2700K in the description to match color temperature to incandescents. Studio lights are about 3200K, but most consumer bulbs are a bit lower. 3000K should also be fine.
December 22nd, 2006, 02:04 PM
I mix tungsten and fluoros and daylight and fluoros all the time, but if they're green, I can't use 'em. With video, sometimes you can get away with using a regular fluoro, but I prefer to make sure that everything is perfect, i.e., no green spike. You may have to throw a Minus Green gel over the CFL's to make everything work properly.
December 24th, 2006, 05:16 PM
I don't like the light from my array anymore.
The hue changes lightly depending on the position of the subject relative to the light, and the board is hard to reposition correcly due to its wideness.
The shadows are not soft - I have multiple colored shadows instead of one soft black shadow. I guess a diffuser of some sort will be useful, but how?
Guess I'll just have to use the standard halogen work lights. They are whiter than incandescent lights, directional, diffusable, and supported well by cameras.
December 24th, 2006, 05:35 PM
Sounds like you'll have to gel the CFL's and then make a frame for the front of the whole unit to hang diffusion from. You can get large chunks of diff, or you can even use tracing paper, just be sure there is enough space between the incandescents and the paper, so the paper doesn't burn.
It's really bad when your lighting gear catches on fire. Like the time I thought it was a good idea to use a paper towel to diffuse my portable flashes and the paper towel went up like flash paper. The flash tube was fine, it was the darned 250 watt modelling light that burned that sucker right up. Tee, hee. It was even more exciting, because I was in someone elses home shooting architecture, or something.
Good times, good times.
December 24th, 2006, 08:30 PM
With the incandescent bulbs removed from my CFL array, I guess I can just drape a plastic diffuser over it to get softer (cyanish) light.
With the bulbs removed, the light is purer and all I need to do is white balance the camera with the light. Or just boost the red channel in post.
I guess I now appreciate the received wisdom that lights of different color temperatures should never been mixed. The result is not pleasing to my brain.
Thanks for sharing, guys.
December 26th, 2006, 01:59 PM
Seun, don't give up on the CFL array yet. A large quantity of daylight-balanced light can be a challenge to reproduce. Your light can still be used as a "moonlight" at night and a way to fill light people backlit by the sun. You probably need a bit of diffusion due to the multiple shadows, but diffusing cool-operating CFL bulbs is easy since you won't risk melting things. You can order diffusion gel specifically made for this purpose or you can try something like very thin cloth or a plastic shower curtain hung a few inches away from the bulbs. Actually, it is good to put the diffusion near the talent, just off-camera.
Using a blue gel to match halogen lights to daylight is very wasteful and you would be using thousands of watts of light to get the same effect as a few hundred watts from your CFL array.
Even more good news: You can use full CTO gel to bring your daylight-balanced CFL array down to tungsten temperature. It is less wasteful to use orange gel on daylight than to use blue gel on tungsten light.
December 26th, 2006, 09:48 PM
Seun, an experiment is neither a success, nor a failure, it merely yields results.
Keep playing and keep experimenting. Keep trying different things.
Just be sure that you cover your ass, if you experiment on a gig. Shoot what they want first, then shoot what you want.
I posted somewhere else about diffusion. Lee and Rosco make four foor wide roll goods that are twenty-five feet long, but you can go to a rental house and buy by the foot, from a partial roll. I do this a lot. I don't have to buy a whole roll and I still get the diff I need. There are also larger "rags" for frames like 6'x6', 8'x8', 12'x12' 20'x20'. 4'x4' frames are handy and you can skin them with whatever diff, or gel you like.
Links for grip mfrs, my post is #12 (http://www.dvinfo.net/conf/showthread.php?t=82073).
January 13th, 2007, 04:58 AM
I've concluded that nothing beats the convenience of halogen lights. They have far better color rendition than flourescents, higher efficiency and whiter light than tungsten bulbs, great portability because just one lamp throws a lot of light. Nothing beats that combination, but my CFLs need not go to waste.