Neutral Density Variable Filter K&F 77mm ND2–ND400 adjustable, gray (SB7798)

The Neutral Density Variable Filter K&F 77mm ND2–ND400 (gray) is an adjustable optical filter designed to control the amount of light reaching the camera sensor. With a 77 mm screw thread and a continuous attenuation range from ND2 to ND400, it provides flexible light reduction equivalent to roughly 1 to 9 stops. The filter lets photographers and videographers use longer shutter speeds, wider apertures in bright conditions, and create controlled motion blur without changing exposure settings or using multiple fixed ND filters.

Advantages

This variable ND filter offers a wide and continuous density range in a single unit, eliminating the need to carry multiple fixed neutral density filters. The 77 mm thread is compatible with many standard lenses, and the gray filter glass maintains color neutrality while reducing light. Its adjustable design enables precise exposure control for both still photography and video work, facilitating longer exposures, depth-of-field control, and smoother motion rendering in bright environments.

Suitable for

• Landscape photography requiring long exposures for smooth water and cloud motion
• Architectural and urban scenes where selective motion blur is desired
• Video recording in bright light when slower shutter speeds are needed for cinematic motion
• Portraits shot outdoors with wide apertures to achieve shallow depth of field

Key specifications

• Thread diameter: 77 mm
• Density range: adjustable from ND2 to ND400 (approximately 1–9 stops)
• Filter color: neutral gray
• Mount type: screw-in circular filter
• Typical applications: long exposure, aperture control in bright light, motion blur and video shutter control

How to use

Screw the filter onto the front thread of a compatible 77 mm lens and rotate the outer ring to adjust the attenuation between ND2 and ND400. Compose and focus the scene before making large density changes, as heavy attenuation will make framing and focusing through the viewfinder or live view more difficult. When using autofocus, confirm focus at lower density or manual focus if necessary. For long-exposure shots, use a tripod and a remote release or timer to avoid camera shake. In video, set shutter angle or shutter speed according to desired motion rendering while adjusting the filter to achieve correct exposure.

Usage recommendations

To minimize the risk of cross-polarization or color shifts at extreme densities, avoid stacking multiple filters and, when possible, test the filter at the intended density settings before critical shoots. Use lens hoods to reduce stray light and clean the filter with a microfiber cloth to maintain optical quality.