Kenko 77mm PL Fader Variable Neutral Density (ND3 to ND400) Camera Lens Filters ND Filter  (77 mm)

Without changing the aperture, the PL Fader allows the freedom to change the shutter speed according to the effect desired With the PL Fader, the shutter speed remains constant for a wide aperture easily creating a blurred background effect Even with a shutter speed of 1/8000 seconds, a large aperture of F1.4 or F1.9 can cause overexposure/highlight clipping. With the PL Fader, this overexposure is eliminated