It can be a big mistake to travel to Japan and walking to a kind of Potterlike hidden street in Honcho, Japan. You might not find any Hogwarts wizards here but nonetheless a magician is residing nearby.
Miyazaki Sadayasu who runs MS Optics, a one-man company that produces limited-run lenses for Leica cameras usable as well on mirror less cameras with adapters.
Over the years, Mr. Miyazaki has created some incredible tiny and small lenses, each of them more unique and even smaller than the last one.
The latest lens is the Apoqualia-G 28mm f/2. He created a 28mm lens far smaller than nearly anything else you’ll find, and on top with the incredibly fast f/2 maximum aperture.
So you see the must have thing and that's the danger in coming here. A danger worthwhile. There is more information on the Japan Camera Hunter site her: http://www.japancamerahunter.com/2016/10/camera-geekery-ms-optics-apoqualia-g-28mm-f2/
Sorry for the image quality. Taken in bad lighting out of time constraint.