PhotographyTips.com - the #1 guide to better conventional and digital photography Become a Member iPhone Posing GuideGuide to Posing the Female Model BookGuide to Posing the Model CD
Search
Login

Member Login

Find us on Facebook
Follow us on Twitter
Find us on Flickr
Connect with us on LinkedIn

SPONSORS

Sell Photos Online

FEATURED SITES


Fill flash

Master fill flash, and you will use it a lot


Fill flash is used outdoors on a bright, sunny day to bring out detail in shadow areas. Conservation officer, Doug Pierce, is captured here returning a fawn to its mother in the wilds.
Fill flash is used outdoors on a bright, sunny day to bring out detail in shadow areas. Conservation officer, Doug Pierce, is captured here returning a fawn to its mother in the wilds.

Fill flash fills in a subject’s shadow area with light. Also known as “flash fill” and “fill-in flash,” it is most often used in portraits outdoors when the subject is sidelit or backlit by bright sunlight. Fill flash is also useful for simulating sunlight on a dull day.

It is not intended that fill flash should eliminate the shadows, since the effect would look unnatural. It should lighten them, reducing contrast.

WHY DO YOU NEED FILL LIGHT AT ALL?

When bright sunlight falls directly onto a subject from behind, above or from a side angle, it produces high contrast. The lighting ratio between shadow areas and highlights can be too great for your film or digital camera's sensor to capture adequate detail in both areas. One solution is to reduce the contrast by using fill light - extra lighting that is added by the photographer to brighten shadow areas so that detail is revealed. Any secondary light source can provide fill lighting - for example, studio lights that bring out detail in shadow areas; your camera's flash unit; or a reflector used to cast light into the shadows.


Although there are numerous ways to add fill light (for example, posing your subject so sunlight falling on a white wall is reflected into the shadow area, using a shiny commercial reflector, or positioning a white sheet to bounce softly-diffused light), one of the most common and easily-achieved ways is to use fill flash.

FLASH IN THE DAYTIME? IS THAT NORMAL?

Many inexperienced photographers are surprised at the concept of using flash in the daytime. They have been conditioned to think that the principal use of flash is after dark, when supplemental lighting is needed to take a picture. But, advanced and professional photographers employ flash so often during the day that many claim to use it for as much as 90% of their outdoors portraits and most other types of shots in bright sunshine. (Perhaps equally as surprising, they may rarely use direct, on-camera flash after dark, preferring to rely on other techniques for lighting when the sun has gone down. This photography is a contrary business, isn’t it?)

AUTOMATIC FILL FLASH IS FAST, CONVENIENT AND EFFECTIVE

When available as an automatic function on your camera, fill flash is a quick way to add light to shadow areas, and since electronic flash is color-balanced for daylight, it can look quite natural. The word “natural” is important. Fill flash must be used in such a way that it produces a natural-looking picture. It mustn’t look like flash was used at all. The background can’t be too dark, or the subject will stand out like a deer in the headlights. The subject must still look like he or she “belongs” in the picture - neither too brightly illuminated nor too underexposed when compared with the surroundings.

Fill flash doesn't overdo it. It provides just enough light to bring out detail in areas that would otherwise be in dark shadow when the sun is behind the subject.
Fill flash doesn't overdo it. It provides just enough light to bring out detail in areas that would otherwise be in dark shadow when the sun is behind the subject.

If your subject looks naturally-illuminated when using fill flash, you have achieved your purpose. Fill flash images should never look as if the flash was the dominant light source.
If your subject looks naturally-illuminated when using fill flash, you have achieved your purpose. Fill flash images should never look as if the flash was the dominant light source.

This means the correct exposure for the area that is illuminated by the flash must also give proper exposure for the area surrounding the subject - the background. The flash must never provide more light than the existing daylight. The light from the flash must at most match the prevailing light and preferably be less than it is so that shadows are still evident, but are lightened - "filled" in, to avoid a featureless, flat lighting look.

If your camera has an automatic fill flash feature, it will do all the exposure calculating for you, providing that your film speed or digital camera's ISO sensitivity setting is not so fast that your camera’s automatic abilities can’t select an appropriate aperture. Use slow film or a slow sensitivity (around ISO 100) to give your automatic fill flash the flexibility it needs.

HOW MUCH FILL FLASH LOOKS NATURAL?

The quick answer, if your subject is backlit, is one to two stops wider than the exposure needed for the ambient light - i.e. the light falling on the background and on your subject's brightly-lit side. So, if your exposure for the background is 1/60 sec at ƒ8, then set your aperture to ƒ8 but set your flash as if your aperture was really ƒ5.6, a lens opening that is one stop wider than the actual ƒ8 aperture you’re using. The one-stop difference will generally provide enough light to illuminate the subject's shadow side so detail is visible but there is still a shadow evident, making the subject look natural and in harmony with the background. For darker, but still natural-looking shadow areas, try a two-stop difference - which many professionals prefer for the increased dimensionality it gives to their subjects.

MANUALLY-CALCULATED FILL FLASH CAN BE TRICKY

Exposure balance can be difficult to achieve if you don’t have an automatic fill flash function built into your camera (or the combination of your camera and its dedicated flash unit). An old photographer's rule of thumb is "Stop for the flash; Shutter speed for the background." This means setting your aperture for the flash-to-subject distance for proper exposure, and selecting a shutter speed that will give proper exposure for the background with the aperture setting you chose.


When using fill flash manually, the most important consideration is shutter speed, since you must employ one that synchronizes with flash. In most 35 mm cameras, the fastest shutter speed you can use with flash (sometimes referred to as the X speed) is 1/60 sec. Therefore, you must choose an aperture setting that (1) will give you correct exposure for the background at a shutter speed of 1/60 sec and (2) will also give you correct fill flash exposure for the subject at 1/60 sec.

If your camera synchronizes with flash at 1/250 sec, you will have a greater choice of aperture settings because you can choose from a selection of corresponding shutter speeds of 1/250 sec, 1/125 sec or 1/60 sec or slower.

Shutter speeds slower than 1/60 sec can also be used with flash, but hand-holding at slow shutter speeds may cause blur, requiring a tripod to steady your camera.

STEP BY STEP MANUAL FILL FLASH

  • First, your shutter speed must be set to its “X” setting, which is its fastest speed for synchronizing with flash.
  • If it does not have an identifiable “X” setting, refer to your camera’s manual for the fastest shutter speed that will synchronize with electronic flash.
  • Set the aperture so that you will have proper exposure for the ambient light at the camera’s “X” shutter speed setting - i.e. as if you were photographing your subject in full sunlight without flash.
  • Turn on your flash, which can be either camera-mounted or off-camera.
  • Since the correct aperture for proper exposure using normal flash is determined by flash-to-subject distance (see Aperture settings for flash), first determine what that distance is for the aperture you have selected.
  • The guide on your flash or your flash manual (or the flash section of your camera’s manual) will tell you what the appropriate distance should be for the aperture setting and the speed of film you are using.
  • This is the distance for normal flash, not fill flash. Normal flash would be too bright. You must now determine what the appropriate distance should be for one (or two) stops more exposure, and that is the distance to use for fill flash.
  • Move the flash further or closer to your subject to the distance indicated in order to obtain proper fill flash exposure for the selected aperture.
  • You can estimate this distance, but for more accuracy, use the distance scale on your lens’ focusing ring. Simply focus on your subject from however far away the flash is from the subject, and read the distance on the lens barrel.
  • Now your flash is at the appropriate distance.
  • If this distance is the same as the shooting distance, the flash can remain on the camera.
  • If not, and you have a removable flash unit and a long-enough extension cord that permits the triggering of off-camera flash, then you can set up the flash at the appropriate distance for fill flash, and use your camera at whatever other distance you wish for proper framing of the subject.

With the main light (the sun) almost directly above and behind the subject, the subject would have been in dark shadow if fill flash had not been used.
With the main light (the sun) almost directly above and behind the subject, the subject would have been in dark shadow if fill flash had not been used.

Subjects that are backlit by the sun benefit enormously from fill flash. Light is added where it otherwise wouldn't be, but not so much that the darkest shadows completely disappear.
Subjects that are backlit by the sun benefit enormously from fill flash. Light is added where it otherwise wouldn't be, but not so much that the darkest shadows completely disappear.

WHAT IF I CAN’T MOVE THE FLASH TO THE RIGHT DISTANCE?

If you can't remove the flash from the camera and the flash-to-subject distance is greater than your desired shooting distance, perhaps your flash is the type that can be set to half-power operation, allowing you to reduce the flash-to-subject distance.


If your flash is built into the camera or is camera-mounted but you don’t have the necessary cable to remove it for off-camera flash, then you’ll need to move the camera to a location where its flash is at the proper distance for a balanced exposure. A zoom lens (or changing to a lens of longer focal length) may still enable you to frame the subject as you’d like, permitting greater camera distance without sacrificing image scale.

If you prefer not to move the camera or don't have a lens of longer focal length, you may be able to (1) bounce the flash onto your subject from a reflective surface (which increases flash-to-subject distance), (2) diffuse the flash so that less light from it strikes your subject, permitting you to move closer (see Softening the harsh light from a flash ) or (3) change to a slower film speed (or digital sensitivity setting) to achieve the necessary aperture in order to use a flash-synchronized shutter speed, but who wants to switch films in mid-roll? Best to load a slower film from the start when you know you’re going to use fill flash. A film speed of ISO 100 is generally slow enough for most fill flash applications. Digital camera photographers can, of course, change their camera's ISO sensitivity at any time, giving them a clear advantage in this instance.

If your camera will synchronize with flash at 1/125 sec or even 1/250 sec (as some will), your choice of film speed or ISO setting becomes less restricted. Having said that, we cannot imagine a bright sunlit day when ISO 100 wouldn’t be adequate.

FILL LIGHT WITHOUT FLASH

Once you have fill flash mastered, you will probably find yourself using it frequently, since it is so effective on bright, contrasty days. However, as mentioned above, there are other ways besides electronic fill flash to bring illumination into a subject’s shadow areas so that detail is revealed and contrast is reduced. Alternate illumination sources include other types of artificial light and reflectors. The advantage of these over fill flash is that you can see their effect as you introduce them, making it simple to adjust their brightness by moving them further away or closer to the subject.

FILL FLASH AND A REFLECTOR, TOO

Combining fill flash with a reflector can produce spectacular, professional-looking images. One simple set-up involves your subject facing the camera with the sun behind and off to one side, fill flash from the front, and a bright metallic reflector behind the subject on the side opposite the sun. This can create a delightful rim-lighting effect that’s very pleasing.

A VIEWER'S TIP

John Cairns wrote in to provide this useful fill flash tip:
"When using 100 ISO, I first meter the subject to obtain correct exposure. Then I set the flash unit to 'think' I am using ISO 200. This gives a one-stop reduction in flash power. If I set the flash to ISO 400, it gives a two-stop reduction in flash power. For me, this is a quick and simple way to obtain the right amount of light for fill flash." Note: Many cameras will automatically provide the right amount of illumination for fill flash, but John's tip is useful when manual setting for fill flash is called for.

Fill flash does not eliminate shadow. It brightens it so detail can be seen while the picture remains natural-looking.
Fill flash does not eliminate shadow. It brightens it so detail can be seen while the picture remains natural-looking.