I've read that there are new samyang lenses coming out specifically for video...I'll find ya a link
SAMYANG T1.5 35mm AS UMC
SAMYANG T1.5 24mm ED AS IF UMC
SAMYANG T3.1 14mm ED AS IF UMC
Cracow, 9th August 2012 – Samyang Optics gladly informs, that Samyang Family has been enlarged by three new lenses dedicated for digital cinema purpose.
Lenses with focal 35mm, 24 mm and 14mm will be available on sales in sequence next week, at the end of August and in September.
The construction of the new lenses has been based on previous types dedicated for photography. Their main feature are racks co-operating with follow – focus system, and a ring rotated continously. Thanks to these alterations it is possible to precisely and silently operate focus and depth of field. Another facility is putting aperture and focus scale parallel to the axis of the lens and aperture marked with number of transmission T. Lenses are compatible with Nikon and Canon cameras.
Prices will be announced soon.
http://www.photographyblog.com/news/samyang_14mm_24mm_35mm_vdslr_cine_lenses/I use the older 28-70mm 2.8L for filming, as well as an 80-200mm 2.8L. I also own the 50mm 1.4 and 100mm 2.8 macro, but haven't used these as much. The primes may render better colors and detail (the 100 more so than the 50), but having the flexibility of a zoom is critical for framing your shots.
Remember, that's my experience filming mostly freerunning and parkour, which is spontaneous, high paced, and not necessarily a great subject to film with a dslr
What I never understand is why OP would ask for "the best lenses for filming" and expect a worthwhile response. Get specific, man!