A few months before getting my AF100, I started testing various C-Mount lenses on my GF1, because I knew that [economical] modern cine-style zoom lens options on a Micro 4/3 video camera were going to be somewhat rare. An old TV-C lens can be had really cheap, and I thought that there might be one or two 1″ lenses that wouldn’t vignette too much on the 4/3″ sensor.
I started with a 16-160 f/1.6 Tokina CCTV zoom, which is a tank of a lens. I was really praying that it would work, because I would love to have a 10X f/1.6 lens to play with. I also picked up a Fujinon TV zoom and a Canon TV-16 zoom. As I suspected, the Tokina and Fujinon lenses vignetted very badly, but the Canon actually wasn’t too bad. It vignettes, but I can see how that in some shooting situations, it could be usable. In the mid zoom range, the black edge comes inside of the frame in the corners, but it isn’t as pronounced in the wide and tele positions. It’s there, but it doesn’t punch you in the face; it’s more of a gentle slap. Either way, it still stings a bit. I will post some real-world clips from it soon.
I think that if I could enlarge the image circle 1.4X, the problem would be corrected. I could handle losing the stop of light, but that would mean it would become a 70-280mm (FF 35 equiv). I don’t really want a zoom that long on the wide end. I may have to relegate the Canon to being a special occasion lens.
I’ve seen mods to mount a B4 2/3″ servo lens onto the AF100. That seems a sound option, especially if you get one of the lenses that has the built-in teleconverter because it solves your image circle problem right off the bat. 2/3″ lenses are wider, which allows more general use after magnification.
Another solution is Abel CineTech’s HDX2 adapter, which is an optical B4 to PL adapter that enlarges the lens image circle from 11mm to 22mm (soaking up two stops of light in the process), and also corrects the 3xCCD optics to project for a single sensor. But, at MSRP US$5500.00, it’s hardly the economical option for low-budget users. On the other hand, if it allows a $15,000.00 servo lens to become usable on larger format cameras, I can easily see how it can earn its keep in a production environment.
So, my search continues. If anyone knows of a C-Mount lens that will actually cover a 4/3″ sensor, please let me know!