The Leica Summicron-R 35mm is an f/2.0 Lens which is compact in size and can be used as all-purpose lens. The Leica Summicron-R 35mm belongs to every Leica R outfit. The lens has to be modified by Leica service center before using it on the original Leicaflex series. The Leica Summicron-R 35mm also works on all the Leica R models.