K&F Adjustable Neutral Density Filter 55mm ND2–ND400, Variable Grey (SB7149)

The K&F Adjustable Neutral Density Filter 55mm ND2–ND400 (Variable Grey) is a variable ND filter designed for lenses with a 55mm filter thread. It provides continuous light reduction across a wide range, allowing photographers to control exposure without changing aperture or ISO. The filter is intended for situations where longer shutter speeds or wider apertures are required in bright conditions, such as landscape and long-exposure photography. It screws onto standard 55mm filter threads and offers a single, adjustable solution instead of carrying multiple fixed-density filters.

Advantages

This variable neutral density filter delivers a broad adjustable range from approximately ND2 to ND400, enabling fine control of light transmission. It reduces the need to swap multiple filters by offering continuous adjustment in one compact accessory. The screw-in design fits 55mm lenses directly, preserving lens handling and balance. By allowing slower shutter speeds or larger apertures in bright light, it supports creative effects such as smooth water motion, cloud blur, and isolated subjects with shallow depth of field while maintaining consistent image quality when used correctly.

Suitable for

• Landscape photography requiring long exposures in daylight
• Long-exposure and motion-blur effects for water, clouds, and traffic
• Portraits in bright light when a wider aperture is desired
• Outdoor videography needing controlled exposure without changing camera settings

Key specifications

• Filter type: adjustable (variable) neutral density
• Thread diameter: 55 mm (screw-in)
• Density range: approximately ND2 to ND400 (continuous)
• Primary function: adjustable light attenuation for exposure control

How to use

Screw the filter onto the 55mm filter thread of your lens until it is secure but not overtightened. Rotate the outer ring to change density and view the effect in the viewfinder or on the camera monitor while observing exposure indicators. When using very long exposures, mount the camera on a stable tripod and use mirror lock-up or electronic shutter options if available to reduce vibration. Monitor for vignetting at wide angles and adjust composition or remove the filter when not needed. Ensure correct metering by checking the camera’s exposure readout after adjusting the filter density.

Usage recommendations

Use the filter with lenses and camera settings that match its 55mm thread to avoid light leaks or mechanical stress. When working at the extreme end of the density range, check for potential color shifts or X-pattern artifacts and adjust rotation slightly to find the optimal position. Store the filter in a protective case when not in use and clean both sides with a microfibre cloth and appropriate cleaning fluid to maintain image quality.