Color & contrast
Below is a portion of a test conducted when the Mini S4 lenses first shipped. The test was comparing the Cooke S4's, Mini S4's, and S4 CXX 15-40mm T/2 zoom. (The CXX zoom test material has been cut from this webpage.) This test was designed to compare the color rendition and contrast between the two lens lines. As you will see, the results speak very well for themselves; practically imperceivable, even in these juxtaposed images. I concluded the color rendition and contrast are virtually identical, however when blown up, stacked, and scrutinized under the most critical of photoshop inspections, I would say the Cooke S4's were one thousandth of a micro-smidge warmer and contrastier. I can't stress enough the small scale of which this observation was made. Both lenses were shot at T/2.8 and from a Red One MX 4k camera file. There has not been any color correction to these files. What you see is how Cooke S4 and Mini S4 portray the same scene.
Last note: The 'Mini S4/i' text designations looked photoshopped because they were. Originally when this test was conducted, Cooke had a different name for the Mini S4 lens set. They were shortly renamed Mini S4's, due to the obviousness of it all, and I had to change the graphics.