Most point & shoot cameras and many DSLRs come with a built in flash. This can be useful when you don’t have enough light for the shutter speed or aperture you desire. In some cases you have little control of the camera’s flash – it decides when it is needed & automatically fires. In other cases, you may be able to control the flash. If so, there are a number of procedures you can use to improve your overall images.
First, don’t expect too much from your flash. Most in camera flash units are only capable of providing light at distances of 10′ – 15′ at best. Trying to exceed this will result in underexposed images, or force the camera to increase the ISO to the point where the image becomes grainy. If you find your in camera flash does not provide enough light most of the time, many cameras include connections for a more powerful external flash.
In most cases using flash will result in “harsher” images. The reason is the flash tube is a small source of light. The smaller the light source, the sharper the shadows it will produce. This is why photographs taken on hazy days look softer than those taken in direct sunlight.
Read on for methods to improve your flash photography:
When using flash, one solution to soften shadows is to make the source larger. Commercial photographers use a 2′ – 4′ diameter device called a “Softbox” to accomplish this. Adding some diffusion material over the flash is one way for the amateur photographer to do this. You don’t get something for nothing. The more diffuse your source the softer the lighting, however since you are spreading the same amount of light over a larger area, you will reduce the amount of light that falls on your subject. Diffusion works well for close up photos; not so well if your subjects are at a distance.
Some sources for diffusion materials include Rosco Cinegel Filters or Lee’s Diffusion Filters. These products are available in a number of different finishes – some offer very strong diffusion, some weak, while others are directional. In addition to neutral color filters, these materials are also available in tints that can color correct your flash. This is useful if your primary light source is tungsten (household lamps) but you want to fill in with flash. Combining two different color temperature sources (in this case the 5000°K strobe with the 3000°K table lamp) will result in difficult to correct color balances. If your white balance is set on auto, it may end up way off from the correct balance. Choosing a tinted diffusion that changes the color temperature of your flash so that it matches that of the tungsten lamps and manually setting your white balance to indoor or tungsten will result in a better photograph.
These filters are also available in hundreds of non diffusing colors. Although you can purchase these materials in large sheets or rolls, most theatrical suppliers and some real camera stores can provide “Swatch Books” for either manufacturer’s products. These are 1.5″ X 3″ samples used by lighting designers to choose the colors they wish to use with theatrical lighting fixtures. Although the theatrical swatch books contain the largest number of colors, the manufacturers also furnish versions designed for the film & video industries that describe the colors in photographic terms. The individual pages are large enough to cover most point & shoot and many stand alone flash units. Swatch books are usually available free if you explain that you need one to choose the color sheets you plan to buy, or, if you can’t convince the dealer that you are going to purchase larger sheets of product, at a low cost. Since they need to be replaced as manufacturers add new colors, you can also ask the dealer for expired books.
Don’t try to use these products as a replacement for lens filters. They are not optically clear – they are designed to color light sources, not placed over lenses.
One additional point – these color filters are useful for adjusting the color of light and/or harshness produced by the fixtures in your RV. They do cut down the amount of light – the swatch books often indicate the transmission factor, but since many 12v lamps have small filaments that poduce sharp shadows, a bit of frost or diffusion may be helpful. Again, the size of the sheets in the swatch book may be large enough for your fixtures; if not, use it to choose the material & purchase a 20″ X 24″ sheet for around $6.00. Sheet material is useful for correcting the color produced by fluorescent lamps.
If your camera can use an external flash, there are a number of things you can do to soften the source. Some manufacturers include diffusers that are designed to cover the flash head so that it can be aimed directly at the subject. They may be provided with the flash unit or as an inexpensive add on.
Another approach: most external flashes are designed so that the flash head swivels. Point it at the ceiling rather than the subject & the light source becomes the entire room. One caution – if the ceiling isn’t white, it may add objectionable coloring to your photograph. If bouncing off the ceiling does not provide enough direct light to fill in shadow areas such as eye sockets or under noses, tape or use a rubber band to attach a white index card directly behind the flash so that the light bounces to the subject from the card & ceiling. There are commercial units designed to do this, but an index card works. I also keep a 1′ square piece of thin white wrapping foam & a rubber band in my camera bag. It works as a reflector or a heavy diffuser, depending whether it is placed behind or in front of the flash head.
As long as I’m discussing add on devices for external flashes, I should mention the “Better Beamer.” This is an inexpensive device that adds a fresnel lens in front of the flash head. It does the opposite of the diffuser – it produces a very narrow beam that produces a small circle of light. Combined with a telephoto lens, the Better Beamer is great for bird & animal photography. By concentrating the light from the flash in a narrow beam, it lets the photographer add fill light at distances of 100′ or more. Better Beamer’s for many different external flashes are available at Amazon.
Another characteristic of electronic flashes is they generally emit light for very short periods of time. This can be useful if you want to freeze the action by using it as the only or at least, the major light source. Many units can adjust the duration of the flash to reduce the amount of light they produce. Placing the flash within inches of the subject may reduce the duration of the flash enough to produce interesting images of water drops, or freeze other fast moving objects.
Of course, if you are trying to blur an image by using a long exposure, the short duration of electronic flashes presents a problem. Some point & shoot as well as most DSLRs provide a solution – slow sync flash mode. When set to slow sync, you or the camera determines the shutter/aperture combination necessary to produce an image without the flash, than fires the flash during the exposure. This may be referred to as “night flash” in your manual or camera controls. Since the shutter may be open for long times (in the case of the Nikon D200 as much as 30 seconds) slow sync does not work well with backgrounds that move. The end result is the backgrounds the flash can’t reach are properly exposed with the ambient light while the flash properly exposes the foreground. Of course, you may still have a problem with white balance if the color temperature of the flash doesn’t match the background lighting. Another place for color correcting plastic sheets!
There are other flash modes available on many cameras. “Red Eye Reduction” is useful to eliminate or reduce glowing red eyes of subjects particularly noticeable if the natural light is dim. Red eye is caused by reflections of the flash off the blood vessels of the retina. Moving the flash even a few inches off axis of the lens will help since it then won’t reflect directly back in the lens. As cameras get smaller, it may become impossible to place the flash tube far enough away from the lens to prevent the problem. The solution is to fire the flash once or twice just before taking the picture. This closes down the subject’s iris so that reflections are reduced. If you have already taken the photograph & have red eye problems, most editing software can post process images to make corrections.
Overall it is worth spending some time with your manual and your camera’s flash to explore how it can be used. Modern flashes can often do far more than just pour light on a subject.