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What creates a calisson-like shaped light bokeh such as this one (made with Arri signature T/1.9) ? The further from the center the more present are the angles, why ?

Arri Signature

Another lens (Zeiss Supreme T/1.8) gives another shape:

Zeiss Supreme

How (where in the lense) to craft this shape ? Yet, why (how) in the Zeiss case, the bokeh looks harder, even though the aperture is the same (1.8 ~ 1.9) ?

  • TIL calisson. Interesting word, thank you! – scottbb Jun 19 '19 at 21:34
  • Do you mean lenticular bokeh? – xiota Jun 19 '19 at 22:32
  • @scottbb Last question remains without answer ! – Soleil - Mathieu Prévot Jun 19 '19 at 22:43
  • The Zeiss lens appears to have been stopped down a bit. I see a nonagonal shape. – xiota Jun 19 '19 at 23:17
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    If by the "last question remains unanswered", you're asking why the bokeh is different between the T/1.8 Zeiss and the T/1.8 Arri, I have to ask, what is the actual f-number used, not the T-stop? The f-number characterizes the geometry of the lens (the focal length divides by the diameter of the entrance pupil), whereas the T-stop accounts for the total light transmission through the iris (including transmission loss of the optical elements). – scottbb Jun 19 '19 at 23:32