The MS-Optics 21mm f/4.5 Perar is, without a doubt the smallest lens I’ve ever shot with on a Leica rangefinder. In fact, it’s probably one of the smallest full frame lenses ever made. Yet despite its size, it still focuses, it still has an aperture control and is even rangefinder coupled. On paper, this thing is a feat of genius. The question is, how well does it work in practice?