Using Flash for Outdoor Portrait Photography, Why?
Have you ever seen a photographer taking an outdoor photo with flash even under the bright sun shine? Using flash for outdoor portrait photography especially model provides several advantages compared than natural light (sunlight) only. Definitely, you can get a punchy lighting to the model face and better lit on the eyes.
Meanwhile, if using natural light, we have to pay more attention into light that falling to the model face. If your model is posing under the tree, her face will looks dappled by the leaves shadow. Often, when we use a natural light, the model face should slightly raised to get a brighter light.
The other benefits of using flash is that we can control the ambient light. Whether you want dark or bright, just set the shutter speed. Just speed it up if you want a dark background, slow down if you want a bright light environment. With flash, we can reduce our dependence with the solar light. Despite it’s cloudy, we still get a strong enough light and sharp result. Even sometimes too sharp and the face texture can be seen very clear.
The weakness of using outdoor flash is when the sun shine is too bright, when the power of the flash can not compensate the sunlight, and a little trouble to set-up flash, lightstand, wireless trigger, and umbrella/softbox. If the combination of flash light and the environment is too different, then there is unnatural impression.
Well, in addition, when shooting with a flash, do not forget to turn off AUTO ISO. Sometimes I got an over exposure photo when using speedlight which is usually due the AUTO ISO system automatically raise the ISO and ignoring the flash, unless you are using speedlight with ETTL. Lightmeter typically measure ambient light and ignoring the flash, moreover if your flash is not the same brand (or manual) with your camera.
Due to the combination of flash and ambient light, the camera lightmeter does not need to be set up at zero point. Usually slightly-under or slightly dark (lightmeter is in minus position). One more thing, each camera/flash has its own maximum sync speed, usually about 1/200 sec for manual flash. Do not use a higher shutter speed, because the image will be striped (some dark, some bright).