Standard lens series voigtlnder nokton lens mount leica m lens speed 14 focal length 40 mm construction prime lens area of use night photography astrophotography indoor photography action photography news photography focus manual focus af motor no internal af motor closest focusing distance 70 cm lens construction groupselements 67 number of aperture blades 10 minimum aperture 16 max aperture 14 coating multicoating mc length 30 mm len