[Please note: This is the original version of the hood, there is now a 2nd version with cutout, alignment marker and slightly wider opening. Both work fine.] This hood fits to the existing bayonet attachment via a very tight friction fit. On first fitting it may feel you are forcing it, but this is normal and the mount has been tested across 3 different examples. The print maybe a little tighter than usual, if this is the case, cleaning out the bayonet grooves will remedy the situation. This hood will also work on the Zeiss 50/2 Planar, tho won't offer as much shading as it's dedicated hood. This is a compact hood for the Voigtlander 35mm f1.4 Nokton Classic lens, as a replacement for the £48+ one that Voigtlander offers. It's more compact and has been calculated to offer greater shading. Because the Voigtlander 40mm f1.4 Nokton Classic is almost the same lens, but will a narrower FOV, this hood will also work for this lens too. It's rectangular cutout is 10% wider than the lens' field of view for full frame, has been tested on a full frame camera without vignetting. On a crop body such as the M8 or NEX ranges, there should be no problem at all.