Photography and electronic flash?

What is the advantages (or disadvantages) of using electronic flash for potraits?

Flash has a constant color temperature.

It's easier to control lighting ratios because you can dial in the power you want. With 'hot' lights (tungsten/halogen) you have to move the lights or use something between the light source and subject to reduce the light. You can use a dimmer (a very heavy duty one) for black & white work. With color, reducing the light level warms up the light.

Most studio flashes have a duraton between 1/800 sec to 1/4000 sec which effectively freezes the small movements models may make, leading to sharper images.

Because the exposure is controlled by the aperture setting, you can shoot off tripod. This is very handy.

You're not liable to burn yourself innadvertently.

They are more convenient on location. If the lights you need for the shoot, plus the power ordinarily drawn on a circuit, is greater than the amperage of the circuit, you blow the breakers. Also, on location, there are battery pack lights and the alternative, a generator is less expensive because the demands it has to meet are less.

Downsides?

They are much more expensive.

I don't have a problem with the modelling lights being 250 watts or so and for the lights I use, they scale to the flash in brightness so I can see more, or less, how things will look. The caveat is 'more, or less.' Many modelling lights are located in a slightly different relationship to the reflectors than the flash tube, so the light is not exactly the same. This is really only important when shooting one of the basic reflectors because most light modifiers (usually a diffuser or bounce) change the lighting in a way that makes this irrelevant.

I'm sure I missed something.

Vance

+ you can control your light
- its not very nice banged off in someones face, and its very unflattering

you need to bounce flash, and pref have a main light and a couple of fills to avoid horrible shadows...

Everyone had an "open" and "closed" side of their face. Our perception of beauty is a balanced face. Using lighting and proper posing, the photographer can balance the facial features for a more pleasing look. As far as using strobes over constant light, the amount of light needed for a good DOF tends to be too hot for people to remain comfortable for any amount of time, so electronic strobes were invented.

To add to what Ace said, radio slaves are now available for about $20 on EBay and work quite well. One of the manufacturers there is the same one who makes them for AlienBees, but it is much cheaper on EBay. If you use AlienBees, they don't kick back a damaging wattage and you can use one wired directly and slave the others with their built in slaves.

For portraits and any time you would like to reduce the appearance of harsh shadows, photographers will pop some "fill flash" into the scene to lighten or "open up" shadow area's.

Especially in backlit scenes, sometimes referred to as 'pro light' where the main light source is directly behind and overhead. The side of the subject the camera is pointing at will be in full shadow, and will be way underexposed. So you need to get some light on the subject, and flash is a convenient way to do it. You can also use a reflector.

There are a few advantages electronic flash has over incandescent (hot) lights.

* You don't have to worry about subject movement when shooting little kids.
* Light conditioners (umbrellas, softboxes, snoots, scrims) are not bothered by the heat when compared to the heat put out by hot lights.
* The clients may feel more assured they are working with a true pro based upon all the expensive equipment.

Disadvantages:

* They are very expensive when compared to a lighting kit with the same number of hot lights.
* It is easier to see now the light is covering the subject when using hot lights (they are the lights first used in studio classes at most photo schools). The modeling lamps on studio EF units are usually less that 250 watts.
* You will need another expensive item to fire them ... some kind of radio triggering device (Pocket Wizard is perhaps the most used)

advantages
short exposure time, ability to capture very sharply movement(the human face changes its appearance roughly once every 1/40th of a second so flash can catch it)
although it can be more difficult to control in terms of contrast etc. than floodlights it runs much cooler, which in a small studio can be an important consideration