Step-up Adapter Marumi 37 mm to 49 mm SB6201 thread reducer for lens filters

The Marumi Step-up Adapter SB6201 converts a 37 mm lens filter thread to 49 mm, enabling the use of 49 mm filters and accessories on lenses with a 37 mm front thread. Constructed from metal for reliable mounting and precise alignment, the adapter is lightweight and compact, making it suitable for travel and field use. This thread reducer allows photographers to adapt lenses of different thread sizes to a common filter size and reduce the need to carry multiple filter sizes.

Advantages

The adapter’s metal construction provides stable attachment and good concentricity between lens and filter, reducing vignetting and misalignment risk. Its slim profile minimizes added bulk while preserving close focus distance and optical compatibility. The simple screw-on design offers quick attachment and removal, and the durable finish resists everyday wear.

Suitable for

• Attaching 49 mm filters to lenses with a 37 mm filter thread
• Standardizing filter sizes across multiple lenses
• Travel and on-location photography where compact gear is preferred
• Using a single set of filters with several small-diameter lenses

Key specifications

• From diameter: 37 mm (lens thread)
• To diameter: 49 mm (filter thread)
• Material: metal construction for secure mounting
• Mount type: screw-on (threaded) adapter
• Profile: slim, lightweight and compact

How to use

Screw the adapter onto the lens’s 37 mm front filter thread until it is firmly seated, taking care not to cross-thread. Then screw the 49 mm filter or accessory onto the adapter’s external 49 mm thread until secure. To avoid overtightening, fasten by hand and, if necessary, slightly loosen to reposition. Remove in reverse order by unscrewing the filter first and then the adapter from the lens.

Usage recommendations

When using the adapter with wide-angle lenses, check for vignetting or edge shading with thick filters; slim-profile filters are recommended to minimize optical interference. Keep threads clean and free of grit to prevent cross-threading and ensure smooth attachment.