Circle or Ellipse: MS Prabhu DOP

Circle of confusion or Ellipse of confusion on a spherical lens :

A Debate from within :

Dear Cinematographers,
Thought of sharing a few (my) insights from (23/07/2025) OPTIMO prime lenses launch event.

No doubt we always had been admirers of Angenieux lenses over decades, and now they are coming up with a set of Primes with a special attractive feature of OVAL Iris as an alternate option to the primitive spherical Iris, thus giving Anamorphic look on a spherical lens with vertically elongated Bokeh.

Angenieux was doing R&D for nearly five years (as they say) to accomplish the new Oval Iris that delivers you an Ellipse of confusion – the Oval bokeh on a spherical lens.
Our Indian cinematigraphers were happily and efficiently working on spherical lenses for story telling, alongside delivering extremely good results through precise compositions until the advent of Anamorphic lenses that changed even the perspective of Fan maidenhair who was compelled to switch over to wide screen viewing and never wished to go back to 1:1.33, the celebrated Academy aperture of all time classics (old is definitely gold).

Off late, we could sense cinematographers in the mainstream cinema struggling to fit their script into the 2.35 aspect ratio, except for going behind grandeur, based on the assumptions that it has to be that way – isn’t that sad…??

We all know that the FULL OPEN aperture number determines the speed of any lens to compete with others in the market.

Though Angenieux proclaims that their new Optimo primes are faster by being at T1.8, I noticed that, it is possible only when we choose to go with the characteristics of the native spherical lens (spherical bokeh).
When it matters to Oval iris, the area of the aperture opening is comparatively lesser than the spherical iris, of course, due to the geometrical parameters that can not equate the area of a circle to that of Oval “within the given lens” and hence the full open iris of T1.8 shrinks to T2.6 on the same lens, when Oval iris is deployed, thus reducing the speed of the same lens.

Any advent will have its own pluses and minuses, but still, we have to wait for the experiences and it’s outcome from our Directors of Photography, who will attempt to experiment and hopefully share their remarks.
Let’s look forward…,

M. S. Prabhu DoP.