How do I prevent the background from going dark when using the flash with a subject?

Question

This is with Flash, short shutter exposure time, and zoomed in

This is without Flash but with long shutter exposure time

when using the Flash the background tends to get dark and the subject gets to be so bright...(notice the boxes and the metal orange gate)

...any alternatives to get both foreground and background to be bright?

Answer 1

That is the most common side-effect of using flash and there are ways around it which depend on your camera:

• On the Automatic side, if your camera has a Fill flash mode, that is the one you want. Some cameras lack this mode but if you choose Slow-Sync you will get similar results (depending on the camera).
• On the semi-manual side, you need to slow down the shutter-speed. Flash is very fast, so changing shutter-speed as no effect on its illumination but will allows more exposure for everything. You will probably have to dial-down Flash-Compensation at this point because the foreground will also get more exposed by the longer shutter-speed.
• On the manual side, setting your flash to manual power usually does the trick. You still have to select an exposure which will expose properly the background and most likely the foreground, so expect to set the flash to a low power.

Answer 2

There was evidently not sufficient ambient light for a correct exposure at the settings you used. The solutions are:

• Light the background too -or-
• Use a slower shutter speed, reduce the intensity of the flash, and don't change your aperture

Light falls off in diminishing squares and the background in your image is far enough away that the single light source could not light both the foreground and background correctly. It's about the distance from the light source to the object that's being lit; not the distance from the camera to the object. So, lighting the background would place a light source close to the background.

The alternative solution of using a slower shutter speed basically allows you to expose more for the ambient light than for the short-duration flash. Note that it is key to reduce the amount of flash used in this scenario, as the foreground will be way overexposed if you allow it to remain completely powered up.

Answer 3

One simple solution is to not use flash at all, or blend the flash with ambient light. Many answers have addressed these points already so I wont duplicate the advice.

However, flash is often used due to not having enough ambient light, so the above is not always an option.

The problem of bright foreground / dark background exists due to the inverse square law. Simply put light spreads out and loses it's illuminating power quicker and quicker as you move further away. A light at 5 meters has sixteen times the illuminating power as a light at 20 meters.

So what you need to do is place the light in the middle of the scene, so the distances between the light and objects is not as extreme. One way to achieve this is get the flash off camera, off to the side and aim it at the centre of the scene. This however requires an external flashgun and some way of syncing it with the shutter.

Another option is to "bounce" the flash, aim it at the ceiling in the middle of the scene, so that the ceiling becomes effectively a second lightsource that re-radiates light into the scene. This requires a flat ceiling of some neutral colour. Also it helps to have a dedicated flash unit with an pose-able head. However you can get by with a DIY reflector on your on-board flash.

Answer 4

My method to take a good picture in your situation is as follows:

• Decide on the framing of the picture that you want ahead of time. If you use a zoom lens, choose your focal length and don't touch it again.

• Next find the correct exposure for the background, with the flash turned off. For this you can just do trial and error in manual mode, or switch to aperture-priority and let the camera pick the proper shutter speed. Note that if the scene is too dark, then the shutter speed that you need may be too slow for handheld shots, keep that in mind and have a tripod or some other support at hand just in case.

• Now you have the correct exposure for your background. Take note of the ISO, aperture and shutter speed, switch to manual mode (if you haven't yet) and dial those in. Turn on your flash and start playing with your flash power to get your foreground the way you like it. If your background isn't too far away you may find that the flash makes the background brighter, so you may need to revise your shutter speed to compensate for that extra light. At this point your two variables are shutter speed and flash power, by moving these in small adjustments you should be able to arrive at a setting that gets you the picture that you want.