This dedicated Voigtlander LH-7 Lens Hood is specifically designed for use with the Nokton 50mm f/1.1 lens.
Lens hoods are primarily designed to prevent unwanted stray light from entering the lens by extending and shading the end of the lens. In addition, since the end of the lens is extended, you also get the added benefit of some extra protection from accidental impact. This dedicated lens hood is designed to match the specific focal length of the Nokton 50mm f/1.1.
This is a superb product of metal not plastic and adds character to my A7 Sony's. I love the fact that with this guard or hood the camera sets : Perfectly level ... with the 50 mm 1.1 Norton lens. The whole affair is splinted on my camera bodies. Well made and functional , classy gear. A suitable addition to any Voightlander or Lieca lens that it fits. Superb product.
Most photographers with the Voigtlander Nokton 50mm f/1.1 lens would consider the optional vented LH-7 lens hood to reduce the amount of blockage of the viewfinder by the standard (solid) hood. I am not using this lens on a rangefinder camera, but I find this a useful alternative hood even so. The standard hood is a screw-in hood. If one uses a filter, one can put the filter on the lens behind the hood or in front of the hood (the hood has threads on both sides)....if one is concerned about vignetting, probably putting the filter into the front of the hood would be better. However, there is limited space for fingers to screw in (or screw out) the filter into the hood or to remove or replace the lens cap. There is a little more room to do this inside the LH-7 hood while it is mounted. In addition, the LH-7 hood can be removed before installing or removing a filter or cap, since the LH-7 hood is attached by means of a ring - the ring screws into the lens and the hood is placed over the outside of the ring by means of a set screw. Any filter can be screwed in behind or in front of the ring. In fact the threads on the front of the ring are recessed so that many filters will be almost flush with the top of the ring once they are screwed in. Finally, the LH-7 can be reversed on the ring for transport or storage. The standard hood works just fine as a hood, but the LH-7 is a lot more flexible and user friendly.