Nikon PC-E Micro NIKKOR 85mm f-2.8D - Manual (Page 30)

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12. Taking flash pictures using cameras with a
built-in flash
To prevent vignetting, do not use a lens hood. Moreover take
pictures at a shooting distance of 0.6 m or further.
Note: When using the camera’s built-in flash for tilt/shift shooting,
vignetting will be greater than shooting without tilt/shift. For
tilt/shift shooting, use of camera's built-in flash is not
recommended.