Leica 18mm f/3.8 Super-Elmar-M ASPH: Aperture Series 'Aspen Sunstar'
The Leica 18mm f/3.8 Super-Elmar-M ASPH has a 9-blade lens diaphragm which produces beautiful 18-spoke sunstars.
This series shows the sunstar effects from f/3.8 - f/16:
Aspen Sunstar (M240, 18mm f/3.8 Super-Elmar-M ASPH)
Also added is a page on sunstars with a few other examples: