Tungsten or Flash

The question can also be put as, 'hot lights or flash', and I guess we've been hearing a lot about this subject lately. Most of us more casual photographers tend to accept whatever light is handed to us, either outdoors or in carefully picking the best time of day to optimize its effect on our pictures. When we do make our own light it's usually the flash on or near the camera. So lets consider the choices made by a working studio photographer or the choice you might make if you set up a still life shot in your own temporary studio.

Both forms of lighting have strong points and weak points and both might see use in the same studio but definitely not for the same subjects. Tungsten lights, the big hot floodlights, are bright and constant so you see the effect on the subject while you're working with it. Even if you have no idea how to start when lighting your still life, the constant light makes it easy to explore the subject. Just grab one (turn off the rest) and swing it around your subject from side to side, even toward the background and overhead. When you get the best effect, typically with strong side lighting, just plant your biggest light there. It is now the main light. Are there some excessively strong shadows? Just fill them in with a weaker light near the camera or wherever needed for best effect. How about some extra highlights for a bit of sparkle. Just position a couple extra, weaker lights in the right spots, but keep in mind the general rule of good lighting. There should be only one shadow. Any shadows from the secondary lights can be minimized by diffusing them or by careful placement. Another, effective way to achieve a shadowless fill-in light is to substitute a large white card on the side opposite your main light instead of the fill light. The bounced light is from such a broad source that it leaves no shadow, and it often provides some nice secondary highlights.

Tungsten lights can come in smaller or larger reflectors, the larger ones giving softer edged light especially when diffused. They also come as spotlights, rather heavy and expensive unless you can find some used ones. They provide a tight beam of light whose spread can usually be varied with a sort of focusing arrangement. You can sometimes find deep, narrow floodlight reflectors which give a spotlight effect at a lower cost. While the "official" application of spotlights is to produce bright, hard edged light, I often use them for the opposite effect. Sometime the large white bounce card just doesn't lighten shadows enough, so I beam a spotlight on it from the opposite side to boost the fill effect. The tight beam of the spotlight can be directed so it does not hit the subject itself, though a set of 'barn doors" is sometimes needed to cut off stray light.

Here's an amazingly cheap trick that only tungsten light can do. Lets say that you have a complex, detailed subject that requires enveloping, almost shadowless light. Since tungsten light is not really very powerful you can extend the exposure time to several seconds by using small f stops (great depth of field too). Now instead of worrying where the best light placement should be just open the shutter, pick up a small floodlight and "paint" it up and down and left and right around the subject, then close the shutter. If -you've moved quickly and randomly enough you have pretty well surrounded the subject with soft light.

So these are the advantages of tungsten light. It's cheaper since two or three hundred $$ can get you a gaggle of lights and stands (but spotlights cost more). The biggest advantage is that you see the light as you are using it and can play with it till you achieve the perfect effect, and of course tungsten is usually the way to go to get all the bright, hard edged lighting effects

How about the down side? Plenty here unfortunately. While it may look bright it's still pretty dim compared to flash or daylight. That means exposu
re
s long enough to be confined to a tripod. That's okay for the still life which is not going anywhere in a second or two, but even at 1/ 15th to 1/60th at larger f stops it may not be fast enough for people pix especially kids, and other kinds of moving subjects. And don't think you can just pour on more wattage to overcome tungsten's inherent weakness. You'll probably start off with a couple 500 watt units, then add a couple more for more flexible lighting. Try doubling or tripling those numbers and pretty soon you'll blow the doors off the breaker box. Also when you're on the other side of the camera, sitting there as a patient subject you find that the big wide flood that you prize for its softness is really a big, angry hot inferno, hard to bring your eyes anywhere near. The heat can even be a problem for static subjects. Let's say you're trying to take a picture of a whipped cream topped ice cream sundae. How many seconds would it last under that blast before becoming a messy puddle?

This is where flash (strobe) lights come in. Flash is both fast and powerful. Even the smaller portable flash unit that sits on top of your camera puts out a peak intensity that equals sunlight anywhere from 20 to 60 feet away and big studio units can have up to twenty times that power. With all that light output it is easy to create the very soft light generally desired for portraiture by bouncing it off a broad reflective surface like an umbrella or putting it through a lightweight softbox. The light is so soft edged that secondary shadows are much less perceptable. The speed is so high that your shutter speed is almost irrelevant, as long as it's high enough to exclude ambient light (which might be off color or lead to motion blurs), and low enough that it isn't cut off by the camera shutter (too high a speed with a focal plane shutter). That means motion filled work scenes, lively kids and even trembling adults and are no problem. Strobe is also cool. After shooting that ice cream sundae it still looks good enough to eat (go ahead, have fun).

The big downside to strobe, especially in its early years was that you couldn't see exactly what kind of light you were getting as you set up the picture. At first the photographers had to rely on experience and experimentation --- not very good clues if you had to be very exact. Modeling lights came along some 20 or 30 years ago to give you some idea of the lighting effect, but for quite a while they gave no clue to the intensity of the light. More recently proportional modeling lights appeared which dimmed and brightened as you switched to higher and lower flash outputs. Only in the last ten or fifteen years have the continuously proportional, continuously variable ('tracking) monolights appeared, where each individual light can be separately controlled. These achieve pure nirvana in portraiture. You can set up the main light, then go to the fffl light and slide the zipper up or down till you get the exact lighting ratio you want --- and when the flash goes off, you get just what you saw. Of course the modeling lights are still rather dim, since too much would create ghost images, so you have to all but eliminate house lights to correctly evaluate them.

While the soft look became inseparably connected to strobe in earlier years, there's no reason that you can't take off the umbrella, turn the lights around and achieve the more hard edged look of tungsten. At first, you had little control over this look but gradually the same variety of accessories like wide or narrow reflectors, barn doors and spotlights have appeared for use with flash so similar effects can be had.

The biggest downside is higher cost for strobe equipment --- up to ten times higher for equivalent capabilities. Another downside, since the light is not continuous you can't just read the exposure with your camera meter. For that you need a flash meter. Dedicated or auto flash also takes care of getting the right exposure but none of that applies to t
he big
studio setup. Those big lights are so dependent on separate flash metering that they don't even bother with suggested guide numbers.

Neither light is good at everything and it's less than ideal when either is misapplied. Some long time studio people who have used their strobes for models try to use them for still life shots and find that even with the big blast of light, there's not enough at the tiny f-stops they need (like F64). So they use multiple "pops". Dumb, dumb -- they would be better off with tungsten. And some habitual tungsten users fry their hapless subjects --- not very cool. So either light sources can be a great tool in your picture taking toolbox, but try to use the right one.