Neutral Density Variable Filter K&F 37mm ND8–ND2000, Adjustable Grey (MPN SB6571)

The K&F 37mm Variable Neutral Density Filter (adjustable ND8–ND2000) is a compact screw-on grey filter designed for lenses with a 37mm thread. It provides a continuously adjustable density range equivalent to approximately ND8 up to ND2000, enabling precise control of light entering the lens. The neutral grey coating preserves color balance while reducing exposure, making the filter suitable for slow shutter speeds, controlled depth of field, and motion blur effects in bright conditions. Its slim profile and straightforward screw-on mounting make it convenient for on-location photography and video capture with compatible 37mm lenses.

Advantages

The variable ND design replaces multiple fixed-density filters by allowing a smooth transition between lower and higher light reduction without changing glass. The neutral grey formulation maintains accurate color rendition across the adjustment range. The compact, low-profile construction helps reduce vignetting on wide-angle lenses with a 37mm thread and ensures stable attachment during handheld shooting. The screw-on mechanism provides fast installation and removal, suitable for quick changes in changing lighting conditions.

Suitable for

• Long-exposure landscape photography to smooth water and cloud movement
• Portraits and video requiring wider apertures in bright light
• Creating motion blur for moving subjects such as traffic or waterfalls
• On-location run-and-gun shooting with compact cameras and lenses

Key specifications

• Filter type: variable neutral density (variable ND)
• Thread diameter: 37 mm
• Density range: approximately ND8 to ND2000 (continuous adjustment)
• Optical effect: adjustable light reduction while maintaining neutral color balance
• Mount type: screw-on filter ring
• Profile: slim/low-profile design to minimize vignetting

How to use

Screw the filter onto the front thread of a compatible 37mm lens until snug; avoid over-tightening. Rotate the outer ring to change the density and observe the exposure or histogram on your camera to reach the desired shutter speed or aperture. For long exposures, use a tripod to prevent camera movement. When combining with other filters, attach the variable ND closest to the lens and check for cross-polarization or X-pattern at extreme settings; reduce the rotation degree if unwanted artifacts appear.

Usage recommendations

Monitor exposure, white balance, and focus when using strong attenuation. For very long exposures or critical color work, verify results with test frames and adjust composition or settings accordingly.