Looks like to shoot 4k and use M4/3 lenses, you may need to allow a little vignetting. Would be interesting to see how various M4/3 lenses fair in the 86% 4k scan mode, as it looks like any mode with more crop than that, reverts to HD. Images from video above.

SO if I use DX format lens on booster (to m4/3 obviously) what % of sensor will be covered or DX on regular adapter?

other words I still can't figure this out how shot on full "DX size" sensor if its m4/3 mount?

@konjow Appears to me the LS300 supports full S35 100% crop with Nikon DX lenses. With Lumix lenses, you'd need an 80% crop to reduce the sensor to MFT size, but you'd still be able to record in 4K as well as 1080p resolutions. With narrower than 80% crop, you could shoot only in 1080p.

I really want to see some more footage with this, shot with nice glass. So far its lacking a bit of magic somehow, not helped by the fact that they always seem to be shooting 30p.

The Japanese link above lists the crop ratios available in the LS-300 menu:

100% - Super 35 - PL mount, 35mm still lens

97% -　　

95% -

92% -

87% -

86% -

80% - MFT - Micro Four Thirds lens

76% -

72% -

67% -

63% -

59% -

54% -

52% - Super 16 - C mount, 16mm cinema lens

47% -

43% - 2/3 inch - B4, B3 mount, ENG lens

In 4K resolution, you can shoot in sizes from 100% down to 80%.

In 1080p resolution, you can shoot in sizes from 100% down to 43%.

@RRRoger No, at 80% you get the full amount of light the MFT lens projects into a 16x9 frame within its image circle. What you don't get is the full APS-C sensor with its 1.5x crop factor. You instead get an MFT-sized rectangle centered within that sensor, with about a 2x crop factor. In effect, you are digitally zooming into the sensor to match its frame size to the image circle of each lens.

A more in-depth making-of is available as well :

RRRoger, that will make no difference. The Rokinon lens is a lens that easily covers S35 - whether you choose the lens with a MFT-mount or Canon-mount or Nikon-mount (or whatever). It is a S35 covering lens on which you can choose the mount. No matter what mount you choose when purchasing the lens - it will always cover S35.

There do exist "true MFT"-lenses (so-to-speak), which are likely to cover just an MFT-sensor sized area. For those lenses you need to set the VSM to MFT (80%). There will be no difference in light sensitivity (as the pixelsize can't change of a sensor).

@RRRoger No, it makes no difference - only the maximum aperture of the lens will make a difference is how much light you need for your shot. The advantage of the Rokinon or SamYangs over true MFT lenses would be: 1) focus can be shallower due to larger sensor surface 2) S35 is a "known" sensor size for professionals - so you know which focal length results in which angle of view (the last thing is actually explained in the interview (somwhere around the 5 minute mark) :