M30.5x0.5 male to M42x1 male thread adapter

• Front side - M30.5x0.5 male thread
• Rear side - M42x1 male thread

This adapter allows reverse mounting of lenses with 30.5mm filter thread.

Known compatible lenses:

• Schneider-Kreuznach Componon 4/28mm (trick is used - the adapter is mounted to retaining ring instead of filter thread, so you can adjust aperture value)