Just as with exposure compensation, flash compensation allows you to change the flash output in increments of 1/3 of a stop. You will probably use this most often to tone down the effects of your flash, especially when you are using the flash as a subtle fill light (Figures 8.6 and 8.7).
The Flash Exposure Compensation feature does not reset itself when the camera is turned off, so whatever compensation you have set will remain in effect until you change it. Your only clue to knowing that the flash output is changed will be the presence of the Flash Exposure Compensation symbol on the LCD, so make sure you check it. (It disappears when the compensation is set to zero.)
Using the Flash Exposure Compensation feature
- Press the Flash button.
- Rotate the Front dial to adjust the flash compensation in 1/3-stop increments (left to subtract and right to add) from –2 to +2.
- Take the photo.
- Review your image to see if more or less flash compensation is required, and repeat these steps as necessary.
The basic idea behind the term flash synchronization (flash sync for short) is that when you take a photograph using the flash, the camera needs to ensure that the shutter is fully open at the time that the flash goes off. This is not an issue if you are using a long shutter speed such as 1/15 of a second but does become more critical for fast shutter speeds. To ensure that the flash and shutter are synchronized so that the flash is going off while the shutter is open, the G12 implements a top sync speed of 1/2000 of a second. That’s quite an improvement over most DSLRs that use a physical shutter and sync only at 1/200 of a second. If you did use a faster shutter speed, the shutter would actually start closing before the flash fired, which would cause a black area to appear in the frame where the light from the flash was blocked.