I assume your camera is the Olympus D520.

This camera gives you very little control of the flash. The only thing available to you is the ability to change the Exposure compensation.

I would experiment with raising the exposure compensation adjustment a few steps. This may or may not help.

What you describe is quite common. The flash distance on small cameras is usually only about 10 to 12 feet and past that distance, it quickly falls into blackness.

Some cameras have Slow Synchronizing which lets the lens stay open a bit longer past the flash. This adds light to the background. You might check the manual and see if your camera has that feature.

Here is a link to a good writeup on flash for digital cameras:

http://www.shortcourses.com/using/flash/chapter6.htm

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