Lighting Notes

Using a Flash

Flash photography is the use of a camera flash bulb in a variety of possible situations where there doesn’t seem to be enough light. A common use of flash photography is generally  any situation where there is not enough light to take a satisfactory exposure, such as group portraits at gatherings or in lower light situations. But there are many other situations where the flash could be used such as: fill-flash situations when the background is brighter than the subject, using the flash to light up a room and creating better coloring, or using the flash to freeze a moving object in a dark situation.

Problems and Issues

Many people shy away from flash photography because it makes people look bad. Photographs taken with a flash can leave harsh shadows that highlight every wrinkle, turn skin blue, shine a flood light at thinning hair, create hot spots on the forehead, nose and cheeks, and generally make subjects look unattractive. But when there isn’t enough light, sometimes your only choice is to use a flash or not take photos at all. The problem?  Harsh, direct lighting coming from a small source: an on-camera flash. It’s no different than shining a flashlight in someone’s face.

But there’s a simple fix: turn the flash head away from your subject and towards a nearby wall. Bounce flash diffuses flash power over a much larger area which makes the light softer. Instead of coming from a 1-inch wide spot, the light now effectively shines from an area several feet across. A traditional way to do this is to point your flash head at the ceiling, or use a white card to bounce the flash to the ceiling or wall. This can work nicely and ceilings are white more often than not which doesn’t affect the color of the light. But it’s also easy to create new, unflattering shadows under the chin and eyes. And it may not be possible if the ceilings are too high.

The alternative? Point the flash at the wall behind you. The principle is the same but has a few advantages over bouncing the flash off the ceiling. The light comes from a direction more to the front of the subject preventing shadows from overhead sources.

• Both the subject and the near background can be evenly illuminated.
• You can control the intensity of the light by moving closer or farther away from the wall.
• You can control the direction of the light by using a wall to your side and adjusting your flash head and shooting angle.

There are many techniques for overcoming these problems including using bounce flash techniques and controlling the flash output from your camera, but one simple tip is to soften the light from your flash using a diffuser  (see below).

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What is Red Eye?

Red-eye is caused by light reflected off the subject’s retina, and, as a result, a trace of red appears in the eyes of your subject. If the angle of reflection is less than 2.5 degree, red eye will occur. See the figure below. One way to overcome the red-eye effect is to move closer to your subject so that the angle of reflection is larger than 2.5 degree. Or, turn on your camera’s red eye reduction mode (refer to the camera manual). In this mode, the camera fires the flash several times quickly, right before the picture is taken, which forces your subject’s pupils to close down to a smaller size, avoiding reflections.

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Camera Flash in Auto Mode

One of the most difficult tasks in flash photography is understanding how different camera and flash metering modes will affect an overall exposure. Some modes assume you only want a fill flash, while others virtually ignore ambient light and assume that your camera’s flash will be the dominant source of illumination. Fortunately, all cameras use their flash as either the primary light source or as a fill flash. The key is knowing when and why your camera uses its flash in each of these ways. In Auto mode, the flash turns on only if the shutter speed would otherwise drop below what is deemed as being hand-holdable — usually about 1/60 of a second. The flash ratio then increases progressively as light hitting the subject gets dimmer, but the shutter speed remains at 1/60 of a second. A table summarizing the most common camera modes is listed below:

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When should you use a flash?

The trick is knowing when to use or not use a flash. Here’s a couple of guidelines:

1. When to Avoid the Flash

Knowing how to turn the flash off is also valuable because at some events you may be prohibited from using flash. But here are some real reasons when and where you SHOULD consider setting the flash-off mode.

• When you’re shooting far-away subjects that would otherwise automatically trigger the flash— a landscape at dusk, for example. More than a few cameras offer a landscape mode. Setting your camera to landscape or infinity mode tells it that it can’t light the whole scene, so it turns off the flash for you — usually.

• When the quality of light is an essential part of the picture that you want to create. When the flash will probably ruin your shot by lightening the shadows — both big shadows and tiny ones that provide its eye-catching sense of texture. If that’s the kind of image you want to create, turn the flash off.

• When you’re shooting through a window. If you don’t turn the flash off, the reflection of the flash may obscure or obliterate your subject. You can eliminate the reflection by pressing the camera right up to the glass as you shoot. Be warned, though, that doing this may cause the camera to focus incorrectly. If you can’t get right up to the glass, you can sometimes take a picture through a window with flash by shooting at an angle to it. This method is more likely to work if the window is clean. Shooting at an angle also lets you shoot into a mirror with flash without wiping out your subject.

Your camera’s flash probably has a range of about 10 feet. Beyond that distance, it does nothing at all—except waste battery power and annoy people. You know when thousands of flashes go off at a rock concert, football game, or school play? Don’t be one of those clueless people. They’re all firing their flashes for nothing. Do they really think they’re going to illuminate a singer, football player, or actor from 200 yards away?

The second time to avoid using the flash is, well, whenever possible. A no-flash picture is almost always better-looking and more realistic than a flash picture. Of course, small cameras, in particular, may not be able to take certain pictures at all without the flash, like nighttime pictures and indoor shots where people are moving. (Without the flash, you’d get blur.) But there are dozens of edge cases: situations where your camera is convinced that it needs the flash but in fact could do without it; often, it’s just a matter of steadying the camera on something (a car, a wall, a doorway) to avoid blur. If you can learn to identify these situations, you’ll get much more realistic, attractive pictures.

Force the Flash

This may sound nuts. But there’s a very good reason to use the flash even on a bright, sunny day. Suppose, for example, that you’re taking a picture of a person outdoors. (Hey—it could happen.) You aim the camera and half press the shutter button; the camera “reads” the scene and concludes that there’s tons of sunlight. It would never dream of using the flash; it’s not smart enough to recognize that the subject’s face is in shadow. The solution is to force the flash on—a very common photographer’s trick. A fill flash like this makes outdoor portraits look a lot better. It eliminates the silhouette effect when your subject is in front of a bright background. Better yet, it provides very flattering front light. It softens smile lines and wrinkles, and it puts a nice twinkle in the eyes.

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What is Slow Sync Flash?

Slow Sync Flash is a function found on many cameras that tells your camera to shoot with both a longer shutter speed as well as firing the flash. This means you get the best of both worlds above and can both get a relatively sharp shot of your main subject as well as get some ambient light from the background and foreground. Some cameras allow you to access slow sync flash manually and set exposure length and flash strength but on many compact cameras there is a little less control given and it’s presented as an automatic shooting mode, often called ‘night mode’ or even ‘party mode’ where the camera selects the slower shutter speed and flash strength for you.

Rear and Front Curtain Sync

If your camera gives you some manual control when it comes to slow sync flash you might find yourself presented with two options called ‘rear curtain sync’ and ‘front curtain sync’. These two modes sound a little technical but to put it most simply they are the way in which you choose when to fire your flash during the longer exposure.

Rear Curtain Sync – this tells your camera to fire the flash at the end of the exposure. ie when you press the shutter your lens opens up and starts collecting light and just before it closes the flash will fire to light up and freeze your main subject (see the card shot to the left for an example where you’ll see the card trail ending in a nice crisp shot of the card).

Front Curtain Sync – this tells your camera to fire the flash at the start of the exposure. ie when you press the shutter, the flash will fire immediately and the shutter will remain open afterwards capturing ambient light. You might not think there’s much difference between these modes but when you’re photographing a moving subject it can have a real impact. You’ll find many action/sports photographers will use Rear Curtain Sync when shooting with a panning technique.

Read more: http://digital-photography-school.com/slow-sync-flash#ixzz2EcCt6RzN

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What is a hot shoe?

A hot shoe is a mounting point on the top of a camera to attach a flash unit (Wikipedia.com). An accessory shoe is a slot, usually on top of a camera, for mounting accessories such as flashguns, rangefinders, light meters or special viewfinders. A hot shoe is an accessory shoe with added electrical contacts for flash synchronization  One contact is a round, central dot, surrounded by plastic, the other is the shoe itself. This allows mounting a flashgun without a synchronization cable. A hot shoe, also known as an accessory shoe, allows an external flash or other device to be connected to a camera. A hot shoe is a slotted bracket that is generally located on the top of a camera. When an external flash is inserted into the the hot shoe, it’s electrical contacts touch the contacts on the foot of the flash. If there is only one contact (metal circle) then your camera can use a manual external flash, if there are more then your camera is compatible with a dedicated (fully automatic) flash probably from your cameras manufacturer (check your manual). When the shutter-release button is pressed, the flash goes off in sync with the shutter.

Read more: http://www.digicamhelp.com/camera-features/camera-parts/hot-shoe/

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Flash Diffusers

A flash diffuser spreads the light from the flash of a camera. In effect, the light will not come from one concentrated source (like a spotlight), but rather will spread out, bounce from reflective ceilings and walls, thus getting rid of harsh light, and hard shadows. This is particularly useful for portrait photographers, since harsh light and hard shadows are usually not considered flattering in a portrait. A diffusion filter is used in front of a camera lens to soften the image of the scene being shot.

Diffusers help eliminate harsh light and shadows and can help leave your photos looking more natural. Diffusers come in all shapes and sizes depending upon the type of flash you’re using. Some external flash units come with one built in. Other external flashes don’t come with them and need some sort of external diffuser like the one pictured to the right.

Flash Reflectors

In addition to these professionally designed diffusers there are all manner of DIY diffusers that I’ve seen digital camera owners trying. These range from simply placing a piece of semi-opaque sticky tape over your flash (I’ve done this with some success on my point and shoot, to using pieces of plastic from takeout containers through to more involved contraptions involving tissue paper, cellophane and a variety of other types of opaque everyday items.

In addition to this there are a variety of ‘reflectors’ available to purchase (or make) for your flashes also (for example see the one pictured to the left). While a diffuser sits directly over your flash a reflector is usually some kind of white object (card, paper or plastic) that you bounce your flash into to in order to spread the effects of the flash wider through a room and to make the flash a little less direct. Once again they help to eliminate direct, harsh light and shadows and soften the light a little.
If you’re going to make your own diffuser or reflector make sure that you use white, non tinted materials. Otherwise you’ll end up throwing colored light onto the scenes you’ve photographing which will leave them with tinges of that color.

The Soft Box

A Soft box is a type of photographic lighting device, one of a number of photographic soft light devices. All the various soft light types create even and diffused light by directing light through some diffusing material, or by “bouncing” light off a second surface to diffuse the light. The best known form of bouncing source is the umbrella light where the light from the bulb is bounced off the inside of a metalized umbrella to create a soft indirect light. A “soft box” is an enclosure around a bulb comprising reflective side and back walls and a diffusing material at the front of the light. The sides and back of the box are lined with a bright surface – an aluminized fabric surface or an aluminum foil, to act as an efficient reflector. In some commercially available models the diffuser is removable to allow the light to be used alone as a floodlight or with an umbrella reflector. A soft box can be used with either flash or continuous light sources such as fluorescent lamps or “hot lights” such as quartz halogen bulbs or tungsten bulbs. If soft box lights are used with “hot” light sources, the user must be sure the soft box is heat rated for the wattage of the light to which it is attached in order to avoid fire hazard.

Umbrella Reflectors

Lastly, the pros use umbrella reflectors to fire flashes into to reflect light evenly onto their subjects from a wide area.

Read more: http://digital-photography-school.com/using-flash-diffusers-and-reflectors#ixzz2EcKtfyc2

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What is a key light?

The function of the key is to shape the subject. It should draw attention to the front plane (the “mask”) of the face. Where you place the key light will determine how the subject is rendered. You can create smoothness on the subject’s face by placing the light near the camera and close to the camera/subject axis, or you can emphasize texture and shape by skimming the light across the subject from the side. The key light should be a high-intensity light. If using diffusion, such as an umbrella or softbox, the assembly should be supported on a sturdy stand or boom arm to prevent it from tipping over. If undiffused, the key light should have barn doors affixed to control the light and prevent lens flare.

What is a fill light?

A secondary light source, usually at a lower power, can greatly improve portrait lighting. A fill light is the light that makes the “shadow side” of things visible. In photography we define the fill light as one not creating any (as few as possible) visible shadows. The best way to achieve this effect in photography is to place the fill light as close as possible to the camera’s axis. All lights, no matter where thy are or how big they are, create shadows. But… by placing the fill light as near the camera as possible (and above), all the shadows that are created by that light are cast behind the subject and are therefore less visible to the camera. Another way to create fill light is to us a “fill card”. Some photographers use large white cards, foam core, or flexfills. The idea is to place the fill device on the opposite side of the subject as the “main” light, so light is back into the subject to lighten the shadows. How much light do you want to bounce back or add as fill? How close to the subject do we put the fill card? Depends… Fill lights reduces the depth of shadows and softens the appearance of facial features, among other traits. Best of all, a fill light is easy to create: either a simple on-camera flash or a reflector is often sufficient. However, a second light source can just as easily harm portraits.

Understanding the basic principles of three point lighting

Professional cameramen and directors use three point lighting to light their scenes. It uses three lights called:

• key light (main light)
• fill light (secondary light)
• back light (kicker light)

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What is a key light? 

The key light is usually the main and strongest light. If shooting in daylight, your key light will be the sun. Set up your scene so that the subject being filmed is well lit with some shadow to one side.

What is a fill light?

The fill light is used opposite the key light, to fill the shadows. It is often softer/less bright. For example with the sun as your key light you could use a white sheet of card or a white wall to bounce reflection as your fill light.

What is a back light? 

The back light is placed behind the subject, highlighting the outline and separating the subject from the background creating a three-dimensional effect. You could use household lighting such as a desk lamp for your back light.

If you only have one light, this is the key light.
If you have 2 lights, one is the key and the other is either the fill or the backlight. This is used to fill the shadows created by the Key light.
If you have 3 lights, one is the key, one is the fill and the other is the backlight.

 

 

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Other Lighting Tutorials

RESOURCES

Camera Flash: Exposure

http://blog.tracybrownphotography.com/2011/02/what-causes-red-eye-in-photo.html

http://www.cs.mtu.edu/~shene/DigiCam/User-Guide/995/INTERNAL-FLASH/red-eye-reduction.html

http://www.dummies.com/how-to/content/taking-pictures-in-flashoff-mode.html

http://lightandink.com/2011/03/using-a-window-instead-of-a-flash/

Slow Sync Flash

Flash Photography Tips

http://www.steves-digicams.com/knowledge-center/how-tos/photography-tips/how-to-diffuse-your-flash-with-tissue-paper.html

http://www.bbc.co.uk/northernireland/myplacemyspace/promote-your-day-out/with-film/light-and-sound.shtml

http://www.picturesocial.com/photo/tim-and-becks-proctor

http://dptnt.com/2012/01/outdoor-fill-flash-tips/