I have a d3s and use various AF lens. Inside the field of view 2 dark strips have appeared down the left and and right sides - reducing the width of view by about 15-20%. The aspect ratio of the pictures changes and become squarer. The 2 strips reduce the width of the pictures and it is extremely annoying.
It has happened once before and through various button pushing I got rid of it.
Any suggestions on what I have done. Many thanks!