Background of Iris Mechanism

Fig.1. slow motion of the camera aperture(left) and components of the Iris mechanism(right)

As a part of the camera lens, the aperture controls the amount of light entering the lens. The moving mechanism of this aperture is called "Iris Mechanism".

The iris mechanism consists of three main parts such as Base plate, Blades, and Blade actuating ring.

Each blade structure has a four-bar linkage mechanism and all blades moved simultaneously by a single actuator or input force(outer ring rotation).

I would like to find out the length of the link and the number of blades that can achieve optimal efficiency in this mechanism through Kinematic Analysis.

Reference: Nikon D80 slow motion of shutter and aperture, "https://www.youtube.com/watch?v=qfruya5lNow"