It really doesn't make any difference where the lens infinity mark lines up in relation to the top of the camera. There is a wide variance in FSU lenses. The 15mm Voigtlander, with a Voigtlander (brand) adaptor should be closer, but it won't be precisely at 12 O'clock. The FSU lenses and cameras are not calibrated exactly like the Leica's are, but are considered "close enough" for most situations.