just a little note.
in france we have to go thrue test for insurences and buy watching charts for either primo, S4 or Arris on microscope from the negative (even in anamorphic) you can compare the sharpness, softness and differents "warm or cold" ambiance of the image, just on a chartd it's a cheap and easy way to compare lenses, you can also says if old optics are matching together.
primo are warm soft with a verry good definition
S4 are colder but with more light effect and excellent definition
Ultra primes are... close to yhe S4
but that's only my opinion
by