Flash Exposure Compensation


Today’s Question: In a recent Ask Tim Grey you stated: “To help compensate for the issues of having a flash that is so close to the lens, I will more often than not reduce the strength of that flash so it is contributing light that supplements (rather than overpowers) the ambient light.” Would you please expound on how you go about doing this?

Tim’s Quick Answer: The specific mechanics of how to apply exposure compensation for the flash will depend on the specific flash (and camera system) you’re using, as well as your exposure mode for the flash. But as a general rule, you can apply a positive or negative exposure compensation to adjust the amount of light the flash is contributing to the exposure, very similar to how you can apply exposure compensation based on the metering in the camera when capturing a photo without flash.

More Detail: Some flash units include a built-in exposure compensation feature. If the flash is set to a manual exposure mode, instead of an exposure compensation based on stops of light for the flash, there will generally be a strength setting for the flash that you can adjust. This is often expressed as a fraction of total output, for example.

More often with newer cameras, both with built-in flash and external flash units, you can apply a specific exposure compensation setting using the menu on the camera’s LCD display.

The point is that the specific approach will depend on the equipment you’re using. You can obviously check the manual for your specific flash and camera model. In general you will likely find settings on the menu system for your camera, providing an exposure compensation setting for the flash. The camera I typically use, for example, includes a built-in flash. I sometimes use an external flash mounted on the hot shoe, however, and the menu on the camera enables me to adjust the compensation for either flash based on my current configuration.

With previous camera models and older flash units, the compensation was found on the flash unit itself. With the controls on the back of the flash you could apply a positive or negative exposure compensation for the flash, to increase or decrease the amount of light the flash was contributing to the overall exposure.

So again, the specific mechanics will vary based on the specific gear you’re using, but the overall concept is the same. You simply adjust the strength of the flash to change the degree to which the flash is contributing to the overall exposure. Some trial-and-error may be required, but with a little bit of practice you’ll be able to anticipate the degree to which you need to apply exposure compensation to the flash as part of your overall exposure settings.