2. Take an incident light reading with the meter positioned in front of the 18%percent patch on the target.For best results, the aperture reading should be at least 3-4 stops smaller than the maximum aperture of the lens you are using (ex.f/5.6). You may need to adjust the flash power level or distance of the flash heads to achieve this aperture setting. Record the shutter speed set and aperture readout to 0.1 for entering later in the Data Transfer Software.