baby iscorama sharpness?

[silvertonesx24]

Been thinking about getting one, there's one ending soon on eBay now:

 

http://www.ebay.com/itm/Baby-Iscorama-Iscomorphot-8-1-5x-Anamorphic-Anamorphot-Lens-Cinemascope-/290993700462

 

I like the single focus design, but my biggest concern is sharpness. Anyone have any advice on the fastest aperture possible they've dared using this lens? I've used quite a few different anamorphics, and the ones that can't be used below 2.8 or so end up gathering dust for me. I know sharpness is relative, but I need an image that's at least usable professionally.

[Sebastien Farges]

I had it for two weeks and sold it back... The sharpness is not good, the baby Hypergonar or the baby Iscomorphot are better 

[QuickHitRecord]

Here's my test (skip to about the 2 minute mark):

 

https://vimeo.com/60401188

 

I found it to be usable at f5.6 and smaller.

[silvertonesx24]

Thanks- looks like it won't cut it.

[roccoforte]

FWIW I think it's pretty decent when stopped down to about F5.6 - 8. I have taken some nice sharp stills with it; I think a lot has to do with how sharp the taking lens is at infinity. Using my Helios i have to set it at a little before infinity to work at its best. Still tinkering around with it.