This isn't a general interest post. It's simply answering a request for some people who want to remove the hood from their Zeiss 15mm lenses so they can cut the petals off and use filter holders.
Obvious disclaimer applies - doing this voids every kind of warranty, is probably a bad idea, and we don't recommend doing it.
But if you want to, and are handy, taking off the hood / distal barrel piece isn't hard and does not affect lens alignment or centering. So here we go.
The most difficult part, and the only part requiring some special equipment is removing the front cosmetic ring. It's metal and screws off, but is also glued in place. Some Isopropyl alcohol or a thin glue remover needs to be applied around the edge of the ring. A drop or two is enough. We use a syringe but a dropper would work fine. Let it soak in for 10 minutes.
Next you'll need a soft rubber friction tool to unscrew the front ring. We cut the center out of a $5 rubber stopper, but there are a lot of options, including some premade hollow rubber rings.
Use it to unscrew the makeup ring counterclockwise a half-dozen turns or so. This was the hard part, the rest is easy.
With the ring removed you can see the 3 screws that hold the hood / distal barrel on. They are the ones OUTSIDE of the silver ring. The ones inside the silver ring are for the front element. Don't mess with them unless you want to recenter the lens (you don't want to recenter the lens, I promise).
A closeup just to emphasize which 3 screws you remove.
Once the 3 screws are out the hood comes off and you can go mutilate the petals to your heart's content.
Roger Cicala and Aaron Closz