P-iris is a stepper motor to control Iris, and iris value is very accurate ...
But DC Iris is driven by current, and the iris control can not get an exact value. Then can not get an optimal iris value, then the P-IRIS will be relatively more accurate than the DC-IRIS ...
1. Compared to DC IRIS,
2. P-iris encounter strong light, to avoid blur (relative to the DC IRIS)