Super wide angle lens series voigtlnder heliar lens mount sony e mount lens speed 45 focal length 15 mm construction prime lens area of use landscape photography architectural photography focus manual focus circular aperture diagonal angle of view 110 closest focusing distance 50 cm lens type aspherical lens construction groupselements 911 number of aperture blades 10 minimum aperture 22 max aperture 45 lens switches focus ring aperture