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The electronic flash is one of the most useful and under used pieces of equipment going. Mostly it is reached for only when there is to little light. It is also very useful for filling shadows or for putting highlights into a subject. For example: to add sparkle to someone's eyes.
Whenever using flash of any kind be sure that your shutter speed is set to the synchronization speed, or slower.
Many cameras do this for you when the flash is turned on. Should you find that flash pictures are cut in half, one side being totally black, then you did not have the shutter on the right speed.
Look at the shutter speed dial, you will find that one of the shutter speed numbers is
a different color, probably 60, 125, or 250. That is the
one that is theflash synchronization speed for that camera. Not
all cameras use the same speed. Don't assume, look and be sure.
Automatic FlashThis will monitor the exposure and actually turn itself off when the film has been properly exposed.
Some flash units are able to increase or decrease the exposure in one-third stop increments. With this you can create a series of pictures each with a difference in exposure of 1/3 stop . This can be invaluable for tricky subjects. The only real alternative to this is a Polaroid camera where you can determine the exposure by trial and error.
The automatic flash will have a light sensor, a photocell, built into its body or it may use a photocell inside the camera. The photocell in the camera monitors the light that bounces off the film. If you see what looks like a big glass bead on the floor of your camera that may be the sensor for the electronic flash.
The manual flash will provide light, but you must set the f-stop and shutter speed. The f-stop is set according to film ISO and the distance from flash to subject. This is not difficult. The flash has an information scale on it to tell you how to do this. Or you can use the Guide Number of the flash unit, if you know it.
As the flash is usually on the camera, the flash to subject distance is the same as the camera to subject distance, but this is not the case when you use off camera flash.
Exposure is determined by the flash to subject distance.
It does not matter if the flash is on the Moon.
Always calculate exposure in relation to the distance from flash to subject.
Taking the picture. First set the shutter for flash photography. Next, determine the distance from the flash to the subject. When you use off camera flash, remember, the flash to subject distance is what is important. You can achieve beautiful pictures with off camera flash and with multiple flash units as well. For precise flash metering use an electronic flash meter.
Determining Exposure With Manual Flash
The most straight forward and accurate way of determining exposure whit off camera manual flash is with an electronic flash meter. These devices are designed to measure the flash and read out the f-stop to use for a properly exposed photo.
If you do not have a flash meter, don't despair. Read on.
Daylight FlashWhen you combine a flash and another light source both must be considered when the exposure is calculated. There are several ways to do this.
A rather easy way is to set the aperture for the ambient light and then set the flash to provide a stop or two less. In this way the flash is used as a source of fill light.
That means the flash will lighten shadow's and add sparkle to people's eyes. The flash will be set lower in intensity than the main light so the flash will not overpower the photo.
For a complex shoot
First choice: An electronic flash meter. This can save you a great amount of trouble. Set up your lights, fire them and the flash meter gives you the aperture.
Second choice: If you have no meter you will need to do trial and error. Not fun, but easier with a Polaroid camera or maybe the camera you are using has a Polaroid magazine. Note: very few 35mm cameras have this option.
NOTE: Make your exposure notes on the back of the Polaroid picture. There are markers that will do this look for indelible writers like the SharpieTM. Notes are very necessary because after you have shot several pictures you won't know which is which.
Include f-stop, location of flash head(s), diffusers, filters on the camera, power setting of flash or power pack, everything.
Last choice: Trial and error. Set up your flash units, load your camera with film and start taking pictures. the problem is that you will not know what you have got until the processing comes back. So, shoot lots of film.
Simply point your flash at the ceiling or wall. Be aware that you want the bounced light to fall on the subject, not in front of or behind, but on the subject.
An automatic flash setting will take care of the exposure for you.
If you have a manual select one or two more stops to compensate because the light must traveling further and the wall will absorb some. A little experience here will do wonders.
There is one thing to be cautious of here, when bouncing off a colored wall or ceiling be aware that its color can be present in your photograph. That is because what you are actually doing is using a colored source to illuminate the subject. A pink wall will reflect pink light, a blue ceiling will reflect blue light. This is not usually a problem, but you do need to be aware of it. And like most problems in life, when you are aware of them they can be dealt with.
Daylight Flash or Fill Flash
This technique is excellent, even in bright sun. Your flash can be used to:
Fill shadows under eyes, nose, and chin
Set the flash exposure as though the bright background did not exist or set the flash to a lower power than recommended. You are using the flash to add some light, not to provide all the light.
For a flash that cannot reduce its power, cover the flash with a handkerchief the more layers you use the more light you hold back.
How do you know how many layers to use. You test the handkerchief, of course, by shooting some film or by using a flash meter. Use an indelible marker to note exposure information on its edge.
It would look something like this:
One layer: +1 stop
Two layers: +2 stops.
Three layers: +3stops
This technique is an inexpensive way to vary the output of any flash. Be sure to use a white handkerchief, or you will have a colored light source.
With the sophistication of modern equipment you may never need this, but hey, one more arrow in you bag of tricks is better than one less. Or as an old photographer friend of mine used to say, "You never know what problem you'll be up against, and you never know what bit of knowledge will solve it."
Using a Kicker
A kicker is nothing more than a white piece of paper or cardboard taped to overhang the flash tube. When using the flash for bounce lighting the kicker will deflect a small amount of light forward into the subject, filling any shadows created by the bounce light.
Using a SlaveA slave is a light activated device that will trigger a flash when the light from a second flash hits the slave. It's just a light activated switch that you plug your flash unit into.
What happens is that the light from your camera's flash travels to the slave and the
slave triggers the remote flash. This happens very fast. The speed of light, about 186,000 miles per second, is so fast
that you do not need to be concerned about any time delay.
Go take Flash pictures.