Shot this today of the Newport bridge. Sony A7RIII, Zeiss Batis 85mm @f/11, ISO 100, 15 stop ND filter with an exposure time of 91 sec. Focus was set manually on the big rock in the foreground without the filter attached. Obviously on a sturdy tripod with a remote release. The sharpness is kind of wonky throughout the frame with the nearest tower blurred though objects nearer and farther away are sharp. It's not a lens issue or a technique issue--I have to blame the ND filter. It's a Singh-Ray filter which isn't cheap, but sharpness is really wonky for no obvious reason. Things that should be in the plane of sharpness aren't. Not field curvature as the lens isn't known for this and my copy of the lens doesn't have it either. A 10 stop ND filter didn't show this behavior. Hard to imagine that the bridge itself was moving during the exposure as the pattern of spotty sharpness doesn't relate to structural elements. Something commonly seen with 15 stop ND filters? Planning on contacting Singh-Ray as this behavior makes the filter pretty much useless.