C Mount Lenses
 

I just ordered a second hand LEX and have been scouring Ebay for decent Nikons and I noticed that those tiny little C Mount lenses are very fast and very cheap. Has anyone made an adaptor that would accept C Mount lenses?
Is there something in the optics of the lenses themselves that would preclude this from happening, like a dof difference between say a 50mm C mount and a 50mm slr lens?
I saw one lens that was f.9 something and it was selling for next to nothing. Would this work? If so, why isn't it being done?

main problem is c-mount is mainly for 16mm or 8mm film and <1" sensors. they wont cover the 35mm image area and the FFD is quite short i think. its not impossible, but the format limitations would just mean you get less DOF (or at least less FOV and therefore comparably less effective DOF) and more vignetting and need extra macros/achromats to get there. and a lot of the cheaper c-mount lenses werent made for filmmaking... ive seen some c-moutn lenses with horribly bad glass. f1.0 (or even f0.95) sounds tempting but when your "zoom" turns out to be a vari-focal (wont hold focus through zoom) and has horrible breathing and halation... it doesnt seem quite as cool. i happened to find a ridiculously good deal on a f0.95 c-mount lens which is actually quite sharp with little breathing but youd probably have to hire a baby to operate the lens is so small and there is no way there is a follow focus ring that small to go with it either...