Hero image responsive issues

Hi guys,
The hero image I’m using has an object in centre and so the image needs to be entered with the width constrained to the width of the browser window, otherwise the object is cut-off or not centred.

When using the hero image without parallax mode this displays fine (proportioned with window size, not full screen so it crops top and bottom of image, hiding the overflow and image is centred horizontally and vertically in it’s container) but with parallax enabled, the image width is not constrained and it seems to proportionally change with the height of the window as the height increases, the overflow of the width of the image cuts off the edges and focuses/zooms on a point in the image. The taller and narrower the browser window, the larger the image is and the more of it is cropped – on a phone in vertical viewing shows just a small ‘zoomed’ block of the image.

Don’t currently have the page public but I see the behaviour is the same for a fresh install of the theme with the demos and parallax enabled.