Filter step-down adapter B&W 49–46mm (1102858) — for mounting 46mm accessories on 49mm lenses

The B&W 49–46mm step-down adapter allows users to attach 46mm filters, lens caps and other accessories to lenses with a 49mm front thread. Constructed from metal, the adapter screws onto the lens’s 49mm thread and provides a 46mm female thread for smaller accessories. It is compact and lightweight, designed to preserve access to the lens front while enabling compatibility between different accessory sizes for both still photography and video work.

Advantages

The adapter offers a simple, screw-on solution to match 46mm accessories to 49mm lenses without the need to change lenses or use larger filters. Metal construction ensures durable mounting and reliable thread engagement. Its low-profile design minimizes added bulk at the lens front and maintains close filter positioning to reduce vignetting on many lenses. The adapter is reversible and easy to install and remove, making it convenient for quick on-site adjustments.

Suitable for

• Attaching 46mm screw-on filters to lenses with a 49mm front thread
• Using 46mm lens caps or protective covers on 49mm lenses
• Mounting 46mm step-up accessories when a smaller thread is required
• Photography and videography setups where matching filter sizes is necessary

Key specifications

• Input thread diameter: 49mm (lens side)
• Output thread diameter: 46mm (accessory side)
• Material: metal construction for durability
• Mounting type: screw-on (male to female thread adapter)
• Design: low-profile, compact

How to use

Gently screw the adapter onto the lens’s 49mm front thread until it is hand-tight and fully seated; avoid cross-threading by starting the threads carefully. Once installed, screw the 46mm accessory (filter, cap or other screw-on item) into the adapter’s 46mm thread until secure. To remove, unscrew the accessory first and then the adapter from the lens. No tools are required for normal use.

Usage recommendations

When using the adapter with wide-angle lenses, check for potential vignetting with thicker filters or multi-layered accessories; if vignetting occurs, choose slim-profile filters or verify compatibility before extended use. Regularly inspect threads for dust or debris and clean gently to maintain smooth installation and prevent damage.