Combining flash with daylight

Combining flash with continuous light (like daylight)

Indoors, it often works best to use a light modifier like an umbrella but there is nothing against an open flash. Especially outdoors the daylight can provide a lot of fill light. Outdoors I rarely use umbrellas, because then the slightest bit of wind will blow over your light stand and it may damage your equipment or models.

When you take the flash off camera, you need to go to manual exposure: the light meter does not see the flash, so it will make mistakes if you rely on automatic.

You simply make a test photo, and check the histogram. The image on the lcd screen is good for composition and to a certain degree the placement of the light. But it does not show the exposure reliably: when you see it in bright light everything seems dark, when you see it in the darkness everything seems bright. So the histogram can tell you the right exposure.

When you combine continuous light with flash, it is important to keep this in mind:

·         Shutter speed (should be below the flash sync speed): influences the daylight, but not the flash. It does influence the way motion is rendered by the daylight, but the flash freezes everything except the fastest motion like a bullet. This gives interesting options when you photograph a concert with a light show: you can make a sharp image with the flash and light streaks from the light show.

·         Aperture: influences both flash and daylight exposures, as well as depth of field.

·         ISO setting: influences both flash and daylight exposure, higher iso settings give lower image quality, depending on the quality of the camera.

·         Flash output: influences only flash exposure, not daylight exposure.

Eustina posed for these test photos (thank you).

·         Photo 1: no flash, 1/100 @ f4.5 is correct exposure, but Eustine does not stand out very much from the background.

·         Photo 2: I added flash to make her stand out. Also I exposed at 1/250 @ f4.5, so I darkened the background by over 1 stop. She stands out strongly against a darker background.

·         Photo 3 has the same flash setting as before, and the same aperture, so the flash is the same strength. But I exposed at 1/125, so the background, that is lit by daylight becomes one stop lighter than in photo 2

·         Photo 4: 4.5 @ 1/60. Now the background is again one stop lighter than in photo 3. Also you see that the shadows in her face are less dark. Because the daylight comes in stronger. The flash is again the same strength.

·         Photo 5: 4.5 @ 1/30. The daylight is so strong it takes over from the flash, and it overexposes the photo.