More on flash photography
Most of us think of using the flash indoors when there just isn’t enough light to shoot without flash. But flash can help you out even when there is enough light to shoot without it. You can use your flash outdoors to eliminate harsh shadows on faces when the sun is bright. Sometimes called fill-flash, this technique uses the flash to “fill” areas of the picture which are not going to receive enough light even though the overall picture will be well lit. The key point here is to set your camera to aperture priority mode when you want to do fill-flash. Here’s why – if the camera is in program mode or shutter priority mode it will expose the picture for flash only. If you’re shooting a person in one of these modes, the subject will be properly exposed but the background may be very dark or very light. When you change to aperture priority mode the camera will expose for the whole scene and the flash will just add some light.
Even indoors you need to decide whether to shoot in aperture priority or program mode. I used to shoot most everything in program mode when I was shooting people and the people always came out pretty well. Often though, the camera chose a wider aperture than I might have liked so depth of field could be pretty shallow. Now I generally always shoot indoors with flash using aperture priority mode. I choose f8 as a general rule. Typically then, my indoor shots are at f8 and 1/60th of a second.
A quick note about shutter speeds. When you choose aperture priority mode, if there isn’t much light the camera may choose a pretty slow shutter speed. Camera movement could be a problem. There are a few ways to handle this:
- Your camera may have a setting to limit shutter speed in aperture priority mode. Canon DSLR’s have such a setting – it confines the shutter speed in aperture priority mode to 60-200 (1/60th to 1/200th of a second).
- Put your camera on a tripod.
- Increase the ISO until the shutter speed comes out to something you are comfortable hand holding.
In this first rose shot no flash was used. The rose looks okay but the area outside the window is over exposed. In the second shot I used the flash in aperture priority mode. The whole scene is nicely exposed and extra light is added to the flower. I used the built-in flash for this one but I set flash exposure compensation to –1 so the rose wouldn’t be washed out by the flash. For close-up work consider setting flash exposure compensation to –1/3 or more.
|No flash f7.1 1/15 sec||External flash with diffuser f7.1 1/60 sec|
Here’s another example where you don’t need flash but can use it to “fill” areas of shadow. The first picture is no flash. Take a look at the cover of the Above Chicago book. The second picture is with flash in aperture priority mode. See the extra light on the cover of the Above Chicago book. Also note the difference in appearance of the white seashell sculpture.
|Program Mode f4 1/60 sec||Aperture priority mode f9 1/15 sec||Aperture priority shutter speed restricted to 60-200 f9 1/60 sec|
In this example I’m trying to show the difference between program mode and aperture priority mode. All three of these were shot with external flash, with a diffuser, pointed at the ceiling. In the first the camera selects a relatively large aperture so depth of field is shallow. In the second I chose an aperture of f9 and the camera chose a shutter speed of 1/15 sec. Might or might not be okay for hand held. Also notice, as is fairly for shooting toward a window, the outdoors is overexposed. In the third shot I just changed the setting on the camera to restrict shutter speeds so the camera chose 1/60 th. Note that the subject is still about right and, as a bonus, the outdoor portion of the shot is less overexposed.
So, just to recap:
- Use your flash indoors or outdoors.
- Program Mode = Conventional flash shot and Aperture Priority Mode = Fill flash
- Check that shutter speed in aperture priority mode and make adjustments as necessary.