@balazar I did not have a chance to seriously test the teleconverter yet because the Nikon 1 is quite crippled for that, do you think that the HE20-1 is suitable to upscale 16mm lenses to super 16 for the BMPCC? It will likely cover more sensor area than needed so the softness of the edges may be no issue here because only the 1" center is used? I know I will lose light but I would like to be able to use my relatively good quality Angenieux, Schneider and Som Berthiot 16 mm lenses on the BMPCC this way. Second, does anyone have experience with its smaller brother version HE15-1

@balazer Thanks a lot for posting this! It unfortunately does not look really promising, quite soft/unequal sharpness/lack of resolving potential.... I meanwhile cheaply ordered some more of the extenders on Ebay and will see if for video they will be useable after modifying them (for fitting M4/3 C-mount adapters they must be modified, originally they are much too wide to fit, not a hard job though) and adapting them to/optimizing them for specific lenses (the C-mount is not that well defined focus wise and the teleconverter may work better on one lens than on another)......

Does anyone know something about this lens? How much is it worth?

Just tried with video and it seems to vignette much less (slightly different sort of frame than still photo). I've only checked on the camera screen yet and it may be more apparent on bigger screen--cannot really notice it on the small screen.

flablo, it should be possible. I removed a Fujinon 16-160/1.4 from a similar type of housing and it works great. I had to take out a shim from the rear and also adjust the back focus to make it focus to infinity, but it should be possible to make them work. I'm not sure what sensor size these were designed for, but try to mount them on a flat/slim c-mount adapter to see if they cover whichever camera you intended to use them with.

If they don't fit your camera, but covers S16/1", it still might be worth to take them out and sell them to someone with an Blackmagic pocket camera of the Digital Bolex.

Anyone know about the Cosmicar 50mm f1.8? I bought one because I have 25mm and 75mm Cosmicar lenses and really like both, but the 50 seems a little disappointing; it wont focus to infinity and has only 3 iris blades! I was wondering if it's worth getting it machined - the ring at the back looks like you could take 1, maybe 1.5 mm off it, but I'm wondering if that would be enough to get it to focus to infinity? I bought the thinnest adapter I could find, but as it stands, the lens will barely catch the thread, so ideally it needs at least 2mm taking off…

I found a cmount lens on ebay that looks good, according to the sample pictures it looks sharp at the corners ,even on an nex camera http://www.ebay.co.uk/itm/35mm-F1-6-HD-Movie-Lens-C-to-Sony-NEX-3-5-6-7-E-mount-Adapter-Lens-Hood-/171303606237?pt=UK_Lenses_Filters_Lenses&hash=item27e27d97dd

+1 Looks like it has a light vignette in some shots. Save a little more & buy yourself a Nikkor 35mm F2 and be happy.

The GH4's effective sensor area in 3840 x 2160 UHD mode is 16.52 mm diagonally. Compare that to various C-mount format diagonals:

• 1-inch: 16.00 mm. 97% coverage - an almost perfect match.

• 16 mm: 12.70 mm. 77% coverage - crop to 2880 x 1620 in post

• 2/3-inch: 11.00 mm. 67% coverage - crop to 2560 x 1440 in post

• 1/2-inch: 8.00 mm. 48% coverage - use 1080 ETC mode. (same as the GH2 and GH3)

I have all of the sensor coverage percentages in the FAQ at http://www.personal-view.com/faqs/gh2-usage/gh2-usage .

So you get better-than-HD resolution with lots of easily found TV and cine lenses. And trust me, many of these lenses are easily delivering that resolution, at least in the center. (not always in the corners) The GH4 lets you take advantage of C-mount lenses better than any other camera.

2/3-inch 6x zoom 12.5-75 mm f/1.8 lenses are easy to find and easy to adapt to Micro Four Thirds. Just search eBay for "12.5-75 1.8 lens". Suitable 1-inch zoom lenses are harder to find. For those not familiar, TV zoom lenses are almost all two-touch, parfocal, and have a constant f-number across the zoom range. Those are great things for shooting video. Usually you'll need to shim a C-mount lens to make it parfocal, because C-mount adapters are almost all shorter than they should be. Metabones claims their adapters have the correct flange focal distance, but I haven't tried.

Thanks @balazer for the very helpful info!! Do you have a GH4 and various C-mount lenses to test with?
I would love to see samples of the 2.5K using 2/3" lenses!
I have the Canon J6x11-II 11.5-69mm f1.4 that I've been wondering how it would work on the GH4.
And I just acquired a Canon J10x11 11-110mm F1.6 that I'm more excited about now!

Plus my Rainbow 8-48 f1.0 will still work great in ETC mode!

FOR SALE!!

Schneider Variogon 10-100 f/1.8 C-Mount Lens MACRO ZOOM. Get as close as 1 inch away!!!

In mint condition, all rings turn smooth, glass is pristine, no fungus, haze or cleaning marks unlike some junk on ebay.

Ideal for the GH4 and BMPCC.(vignette lightly or use a 1.5x adapter which comes with it as well as the C-M4/3 adapter)

Comes with 77mm lens hood. Can ship worldwide. Would like $300 for this fabulous lens.

Test footage here

Camera not included.