Continuous Lighting question?

[stradibarrius]

I received some gift certificates for X-mas and am thinking about continuous lights for my little studio.
I have looked at several CFL cool lights that say the are "daylight balanced" 5500k. If they truely are 5500k does that mean that I can shoot color film with out having to use my 80B blue filter?
They product description says a lot about digital cameras but nothing about film.

[vinny]

Film? Is that the stuff kodak made?
yes, 5500k is 5500k, on paper. There may be a color cast (likely) they aren't mentioning. Led's are the way to go.

[Jim Jones]

Vinny is right about CFLs. Some are advertised for photography, and may be better than others. A standard for determining this is the C.R.I. (Color Rendition Index). The higher the better. Some of the flourescent lamps that B&H sells have a C.R.I. of 82. Most of theirs don't list the C.R.I.. Even a high C.R.I. might not yield accurate color photographs, since flourescent lamps emit strongly in some colors and very little in others. The right balance of these spikes of color might give a high C.R.I. but poor color in photos or vice versa. I have a somewhat large and heavy Panasonic flourescent bulb with a C.R.I. of 84 and a color temperature of 2800K. It emits pleasant light, but I haven't tried photography with it yet. In contrast, an LED with a C.R.I. of 73 and 4100K color temperature looks unpleasantly blue. Both measure close to the rated color temperature with my old Gossen Sixticolor. I suggest trying photography with any CFL or LED before you buy in quantity. Some with a high C.R.I. are expensive.

[Ben Syverson]

It's not just a question of color temperature—with their spiky light spectra, fluorescents and LEDs can have the effect of shifting certain colors unpredictably. Claims of "full spectrum" are flatly wrong, if not fraudulent.

With that said, I think they would be fine for general stuff. Someone's blue sweater might unexpectedly render as deep purple or something, but unless you're doing product photography, it's probably not the end of the world.

[D. Bryant]

I received some gift certificates for X-mas and am thinking about continuous lights for my little studio.
I have looked at several CFL cool lights that say the are "daylight balanced" 5500k. If they truely are 5500k does that mean that I can shoot color film with out having to use my 80B blue filter?
They product description says a lot about digital cameras but nothing about film.

Take a look at the LED continuous light systems. Kirk Tuck has written a new book covering their use.

[Henry Ambrose]

CRI (color rendering index) is helpful but it definitely does not tell the whole story. 5500K "Daylight" lamps (or any lamps) can vary widely in the wavelengths they emit. You can find this information in Spectral Power Distribution charts that should be available for the better lamps.

So look for Spectral Power Distribution information on the lamp you consider using. The more closely the distribution of the output of the lamp imitates that of daylight, particularly in the sensitivity range of the film or sensor, the better for color accuracy.

Once you get close, a small amount of correction via a CC filter gel will help you fine tune your set up, usually a tiny bit of magenta.

[Robert Ley]

What subject will you be shooting with these lights?
If people, electronic flash is probably best with color film and you could use hot lights with B&W. If you are shooting still life in color or B&W then you could go with hot lights and use your 80A filter to correct for color shift. The 80A is more important with transparency film than color negative.

I shoot still life with tungsten lights and stocked up and froze quite a bit of Fuji NPL before they discontinued it. When I run out of NPL I will shoot daylight color neg with an 80A.

I had always thought that the CFL lights were better used with digital as any color temp problem could be corrected with a custom color balance with the digital camera.

[Ben Syverson]

It's not possible to color correct for lightsources with spiky spectra. Even if you correct the color temperature and get a grayscale rendering 100% perfectly, the spikes can cause a loss of differentiation between hues, or give colors an inaccurately pronounced component (red, blue, green). Since there's no way for software to differentiate between "purple" and "purple that should be blue," they will both stay purple.

The extreme example of this is the orange streetlight that most cities use. They're quite spiky by design, presumably so astronomers can filter them out. But try shooting a Macbeth by streetlight. You can remove the orange/yellow cast with optical filtration or white balance adjustment, but you'll be left with an almost monochromatic image.

Obviously the CFL/LED lights marketed to photographers have more even spectra, but there are still spikes and rough patches. They also tend to be pretty expensive. Unless you're shooting video, why not just use strobes? That way you don't have to worry about shutter speeds and motion blur.

[Uri A]

I don't want to be needlessly contrarian, but I have never seen good light come out of an LED. If you want continuous light, use what the cinema guys use: KINOs or HMIs. Both are expensive, but give perfect daylight.

[Drew Wiley]

Hooray, Ben - finally something we 100% agree about !

[Ben Syverson]

Hooray, Ben - finally something we 100% agree about !
Ha! I'm breaking out the homebrew to toast the occasion!

[Brian C. Miller]

If they truely are 5500k does that mean that I can shoot color film with out having to use my 80B blue filter?

GE Lighting, spectral distribution curves and comparison (http://www.gelighting.com/na/business_lighting/education_resources/learn_about_light/distribution_curves.htm)
Take a look at the above link, and go through the lighting charts. The only bulbs without spikes are the incandescent/halogen bulbs. The real question is, do those spikes line up with the sensitivities on the color film you are using?

There is no panacea here. A halogen lamp has a color temp of 3400K, and a tungsten lamp produces 3200K, so a slightly different filter is required to balance daylight film.

Try out different lamps, and try different filters. The FLD filters might work for what you want with a cheaper flourescent lamp. If you have a color chart, then by all means use it, and make a comparison.

Now, consider this for the digital age: how about color profiling software? If you are making prints from the computer, then buy whatever you like, and use color profiling to adjust the difference between the lamp and film. After all, why not? The profiling software will make the balance for you, no filters required.

[John Flavell]

I have to agree with the sticking to the strobe approach. There's still too much color shift with CFL to shoot money-making projects. You and everyone else will be frustrated. Also, there WILL be a shift as they age.

For b&w, CFL can be very useful.

[E. von Hoegh]

Carbon arc lamps.

[Daniel Stone]

I've come to love HMI since I started assisting. They're daylight balanced, and can be VERY bright(worked a job last year, client wanted motion as well, so we were running a 10K(10,000 watts, 100 amps) Arri through a 12x12 silk. Almost bright enough to warrant wearing sunglasses in the studio! Very warm too!

Older HMI ballasts and heads can be purchased for peanuts these days if you look hard enough. Most will be from rental houses, and will probably be beat to shit. You can get lucky though. I almost bought a 2k HMI kit from a lighting/grip company cleaning out older equipment last week. Coulda snagged it, a few extra globes, and a rolling dolly for the ballast(about 2x the size of a standard car battery) for $100. Not a bad deal IMO. They also had some softbox attachment rings and a full set of scrims for it as part of package deal.

However, You'll need a hefty set of breakers to handle them though, they're power hungry ;).

But they're great in leiu of strobes though, WYSIWYG. Kinda hard to do that with strobes, even with modeling lights on the heads.

-Dan

[r.e.]

Stradibarrius,

I use Dedolight. Not the cheapest option, but worth checking out.

On the broader question, if you are shooting colour, and if you want to use continuous lights instead of strobe, I agree with Uri A and with the sentiment in Daniel Stone's first sentence above.

[Bruce Watson]

I have looked at several CFL cool lights that say the are "daylight balanced" 5500k. If they truly are 5500k does that mean that I can shoot color film with out having to use my 80B blue filter?

As you've no doubt gathered by now, there's a huge range in fluorescent lighting. To answer your main question: with the right lights you can indeed shoot color film without having to use a filter on your camera. Movie studios do this all the time. If it'll work for them, it'll work for you.

That said, there's a lot more to it than just 5600K or not. All 5600K tells you is the balance between red and blue. The rest of the color spectrum is not included in that equation. It is at best a very gross designation, at worst a very misleading one.

For photographic use you'll have to buy fairly expensive lights, both the instrument itself, and the lamps (globes, tubes, whatever you want to call them). The ballast in a fluorescent instrument does effect color output, and it certainly effects frequency which may effect your shutter speed. Magnetic ballasts fire at line frequency (60Hz in the USA) while electronic ballasts that claim to be "flicker free" fire much more often, up to 40KHz or so. Clearly electronic ballasts are the way to go if you can afford them.

The lamps themselves also effect color, more phosphors are generally better than fewer. Low grade 5600K tubes will usually have three, high grade will have up to seven (highest I've seen anyway). This is done to reduce (you can't eliminate) the spectral spikes. Know that all arc lighting (fluorescent, carbon arc, and yes, this includes LEDs as well) has spikes in their output. It's just the laws of physics talking to ya. What you want for photography is to limit those spikes to acceptable levels.

A few companies have done this. Kinoflo (http://kinoflo.com/) is one of them -- used all over Hollywood. Good stuff, expensive, rugged and reliable. Mole-Richardson (http://www.mole.com/) has good lights. Arri (http://www.arri.com/lighting/americas) does. There are of course a number of other companies. Look for used equipment, often from rental houses. They have to turn their stock on a somewhat regular basis just to keep up with their competition, even if their older stock is still in fine working condition. Their loss is our gain.

If you want new, there are some companies that cater to the indy cinema crowd. Not as expensive, nor as rugged, nor as reliable. But if you aren't betting a business on it, they can give you good quality light for a lot less money. One off the top of my head is Cool Lights. (http://www.coollights.biz/) Good reputation.

There are some corrections you can apply at the instrument if you need them. You can often smack down a pesky green spike with a minus green gel (http://www.bhphotovideo.com/c/search?Ntt=rosco+minus+green+gel&N=0&InitialSearch=yes), often a 1/4 minus green does the trick, but different lamps require different amounts of correction.

So... it can be done. There's a learning curve, but it's not difficult.

[stradibarrius]

WOW...like everything elso in photography it can be and usually is an expensive proposition. I had decided a whle back to shot color with my digital gear but I keep wanting to be able to shoot color film as well as B&W. Maybe I should just go back to my idea of shooting with filters.

[E. von Hoegh]

When I was doing color product/tabletop photography I used photofloods, voltage regulator, and filters. Worked just fine. Voltage regulation is important as the color temp. of incandescent lamps is voltage dependent.

[Leigh]

Color temperature (in degrees Kelvin) is only the ratio of red light to blue light, by definition.

It knows nothing at all about green.

You could have two very different light sources, one obviously green and one obviously magenta, with identical color temperatures.

That's why good color temperature meters include a separate green/magenta reading.

- Leigh

[megapickle1]

My experience with CFL lights is that they (mine) have a strong green/blue colour cast and I have to use Lee filter foil in front of the lamps (247-full magenta) to eliminate it 90 %. I´ll try to use flash for colour shots.

George

[Jim Andrada]

LEDs are popular with the video crowd and a lot of folks say a minus green filter is needed when using them.. I think some brands of small camera top LED lighting supply such a filter with them.

Check out the coollights site also dvinfo.net forum

http://www.coollights.biz/index.php

[stradibarrius]

Is it more efficient to place filers on the lights on on the lens?

[Bruce Watson]

Is it more efficient to place filers on the lights on on the lens?

Gels the lights.

That way you can see what you're doing, and meter what's actually hitting your subject. And the filter doesn't need to be as high quality (optically perfect) if you filter the light before it hits the subject. Plus, as lights age they may need some small adjustment in filtering -- two lights in a pair may drift apart. If you are using multiple types of lights (say tungsten and fluorescent) they'll need very different filtering to match each other; you can't possibly deal with that at your lens. I could go on, but you get the idea.

[stradibarrius]

That makes perfect sense...thanks Bruce.