Update
 

I was having the "swirly" problem with an f3.5 lens. I rented a f1.4 and the difference is night and day. The swirly is pretty much gone. I'll post the before & after video as soon as I have the time to import the footage.

From reading prior posts, Lens speed was an issue, bringing about the "swirly," on the XL1(s) with the 300 series.

I'm still waiting for info on speeding up the RPM's on the glass, but it just seems mandatory to use faster lens.

In my humble opinion Zeiss Superspeed lenses are the way to go with the Mini35.

They open at 1.3, and for what it's worth, those lenses were used by Stanley Kubrick all the time.
He shot Eyes Wide Open with it, Full Metal Jacket,...

These lenses are razorsharp, definetlly the way to go.

In my humble opinion Zeiss Superspeed lenses are the way to go with the Mini35.

They open at 1.3, and for what it's worth, those lenses were used by Stanley Kubrick all the time.
He shot Eyes Wide Open with it, Full Metal Jacket,...

These lenses are razorsharp, definetlly the way to go.

Though on a SD camera a super sharp lens isn't very requisite ;)

One of the nice benefits of using the Mini35 is that the wide angle cine lenses do tend to resolve better than video zooms, and small format video is most challenged at wide angles anyway (many small elements in the frame + everything in focus + optical issues with the lens at wide angle=mushiness). This is why telephoto shots on DV tend to look nicer (some would say more filmic) than wide angle shots. However, using a, say, 20mm good quality cine prime will generally present a sharper image than the corresponding setting on the camera's own lens (even, in the case of the Sonys and Panasonics, when you are having to feed the Mini35's image through the camera's lens itself!)

I like the Zeiss Speeds also, but given a choice I would use the Cooke S4's.