Olympus Zuiko 4/3 zooms are f2.0, but require 4/3 to micro 4/3 adapter and don't have OIS and auto focus in video mode. Also, they aren't parafocal, unlike the Lumix 14-140, so focus isn't maintained while changing focal length. Ditto Nikon 14-35 f2.8 35mm SLR zoom, which of course requires an adapter.
Reality is that AF100, like any micro 4/3 mount camera, has an almost unlimited selection of lens options--unlike a Canon 5D, which won't work with many lenses, such as the majority of PL-mount Cine lenses.
Pretty much any prime, 35mm SLR or Cine type can be used. Ditto zooms. Right now there is no Canon L-mount adapter that has electronic control for iris. Birger is supposed to come out with an adapter soon.
I do a lot of documentary work, either run and gun cinema verite style shooting or interviews. Using prime lenses don't appeal to me much because they become restrictive in how I can compose my shots. I'd be forced to either move closer or further away, or constantly switching lenses. So for this reason mostly I'm interested in zoom lenses. Even if I have to purchase two different zooms: a short zoom, like a 14-50 and a longer zoom like a 50-150.
So excluding expensive prime lenses, and expensive ENG lenses, is my best bet SLR zooms?
Is there a resource somewhere that explains the different mounts and what kinds of lenses come on those mounts? PL, EF, EF-S, micro 4/3, 4/3, 2/3, etc.
ENG lenses aren't an option because they won't give you full coverage due to the large sensor size of the AF100(4X as big as 2/3"). If you want a fast zoom that offers a wide focal length range, you either buy a Cine zoom, big, heavy, expensive, or two zooms to give you the coverage, like the two Olympus f2.0 4/3 zooms.
I have a set of Nikon 35mm SLR manual primes with focus gears added. I always use the 50mm f1.4 or 85mm f1.4 for interviews. I also bought the new Arri Alura Zoom by Fujinon. It's 18-80mm, T2.6. It's also big, heavy and expensive!
I think you can pretty much choose any lens that interests you and know that there is an adapter for it. The exception is the Canon L series as far as electronic iris and focus interface, but that will change shortly. Again, I can't think of a large sensor video camera that offers as many lens options available.
The lens selection in M-4/3 mount is limited for zooms. Primes are plentiful, but if you are doing "documentary" work, you may want to stick to a 1/3 or 1/2 sensor camera with a long throw zoom. The larger the sensor the larger the zoom lens. m-43 is similar to 35mm standard aperture, so get used to having a zoom lens larger and heavier than the camera! Just a reality of dealing with a large sensor.
I shoot with the Canon 7D, and will be adding a 1/3 chip camera for long takes that I don't need the low light capability or narrow depth of field look. That is the only advantage of the 7D, certainly not the ergonomics or 10 min run time or dual system sound!