Flash photos made simple
How to set your camera for successful flash photos indoors and outside
For some reason, flash photography is the most scary type of photography, and frequently it’s down to not understanding the process of capturing a photo, where there are two kinds of exposure happening at the same time. You can easily categorize flash pictures in to fill-in flash and just flash. Fill-in flash balances any ambient light with the flash, and just flash ignores or eliminates the ambient light.
In daylight, where you may want to light part of the frame with flash, you decide how you are going to capture the ambient light. A good start is to use Aperture Priority in daylight. Take a shot without a flash and look at the part of the frame that is only daylight lit. Skies and distant backgrounds all stay the same when the flash fires. If the background looks okay, then switch the flash on, set to E-TTL and take the photo. In most cases this works just fine. If you prefer Manual mode on your camera, use Manual, set the exposure for the background then use the flash set to E-TTL. Avoid using ISO AUTO, as this works fine until the flash is turned on when it jumps to ISO400.
In low light, you have to make the decision as to how the background is captured. Inevitably your shutter speed will need to be slower to capture the ambient light. For me that usually means a minimum of 1/30 sec or 1/60 sec to avoid camera shake and subject movement. I’d select Manual exposure on the camera, dial in the shutter speed, aperture and ISO to make the environment look as I want, either make it black with a faster shutter speed (but not faster than the camera’s flash sync speed eg 1/200 sec) and low ISO, or slow the shutter and raise the ISO to lighten it. Then switch the flash on, set to E-TTL, and shoot.
In either situation, if the flash-lit part of the picture is too dark or light then use the flash exposure compensation setting, either on the flash or your camera. It’s completely separate from the regular exposure compensation, so make sure you get the right one. Both these approaches work equally well for on-camera and off-camera flash. I’d say that 90 per cent of my flash photos are taken with manual exposure for the ambient light and E-TTL autoexposure for the flash. Off-camera flash just adds to the options for more interesting light on your subject.