Built in ND filters are great. They let you shoot wide open in bright light, giving you control over depth of field. But that control is typically limited, because the amount of ND is only variable in very corse steps.
That’s all changed with Sony’s PXW-X160, and it’s a feature we missed when we first saw the camera.
Sony’s variable ND filter actually has 128 “steps” but in practice changes appear to be gradual and continuous.
This is a really big feature because it means that the camera can handle extreme changes in lighting without the ND changes being visible.
There’s still a conventional mechanical ND filter in addition to the continuous one, in case you want to work the conventional way. The new filter works by gradually dimming an LCD panel to block incoming light.
We’ve got a video from Sony below that shows how this actually works. It’s quite amazing how precisely you can adjust the depth of field by changing the ND setting.