Don't give us the EXIF data, tell us what the camera was set to, including ISO.
The Rokinon for Canon is not chipped, so the camera has no idea what the lens is set for, therefore can't put it in EXIF data. For Nikon, there is a chipped version as well as the less expensive unchipped. I have the chipped version myself, and I like the lens. It's a lot of fun!
The image is obviously underexposed. You say the camera is in manual, and 1/4000 is a very fast shutter. You said you set it to 1 second and it was the same, but we didn't see the image there, just you saying it was the same. Still no idea what the aperture or ISO is set to.
I think the camera can be set to manual yet the ISO still could be automatic, which means the meter is STILL adjusting your exposure, even though you're in M mode, as you're only controlling two sides of the exposure triangle. If ISO is Auto, you DON'T have manual exposure control.