Uses of Iris Blades ?

[Ram Nanda]

Apart from shape of bokeh, what are the pros and cons of having more iris blades ?

Cooke S7i (image circle : 46.3 mm)         - 9 blades

Zeiss CP3 (image circle : 46.3 mm)         - 15 blades

Zeiss Supreme (image circle : 46.3 mm) - 16 blades

Arri Signature (image circle : 44.7 mm)   - 11 blades

Leica Thalia (image circle : 60 mm)         - 15 blades

[jacob larsen]

You will find an excellent read about this exact question here: https://www.dpreview.com/forums/thread/4325273

A few key-words: star-bursts, diameter of lens-house.