Of course, it’s not just flash that makes a great photograph, it’s other light sources as well. There are four light sources in the photograph here 1) Flash, 2) The Fairy lights 3) The sky 4) The lamp in the background. All of them combine to create a compelling and colourful photograph. In order to capture all of these I used a relatively long exposure to capture the ambient and low levels of light, while the flash illuminated the subject.
The important rule with flash is that shutter speed has absolutely no effect on the flash exposure – only the aperture does. Why? Well, your typical flash head will deliver a burst of light at around 1/4000 of a second, so regardless of what you do with your camera’s shutter speed, it won’t have any effect. Therefore you have to use the aperture to control exposure.
In the example above, the subject is still sharp because the ‘ambient’ light she was in, wasn’t strong enough to hit the sensor, hence it was only the 1/4000 blast of light that lit her – therefore she is perfectly sharp, even though the shutter speed was around four seconds! I probably haven’t explained that at all well, but will do so in a later post.