Yes, it's at 10mm f/2 so suspecting wide aperture. But it also happens at 14mm @ f/2.8 with the Nikon D810 I tested. Similar symptom as the reviewer with the 14-24 f/2.8 Nikkor experienced which can be fixed in Photoshop. @f/4 and up; no problems.Presumably that's a 'speed booster' which means it's no longer 14mm. IIRC the combination of 14mm + booster =~9.5mm filter requirements for that would be more demanding than the lens alone.