Because the metering systems of this camera, both ADI and P-TTL use the reflection of pre-flash to adjust flash output, the previous type external flash units that do not support pre-flash function cannot be used.
Such external flash units will fire with full output when attached to the DiMAGE 5/7, which requires the manual calculation of exposure from the aperture setting and the subject distance. General formula to calculate an optimum exposure is as below:
Guide Number / f-Number = Subject Distance (at ISO 100)
If the Automatic setting of camera sensitivity is selected, turn the control-dial for two clicks to select a larger aperture opening by one-stop. e.g.) f/5.6 to f/4, f4 to f/2.8 Minolta's X-series flash units have no compatibility with this camera.