II have just bought a second-hand DA 35mm 2.4. When I checked it out with the seller, I noticed that the front seemed different than what I remembered from the internet, but thought nothing of it, since the lens was in perfect condition in every other way.
Coming home, the difference kept popping up in my mind, and, sure enough, the front didn't look at all like in the review images. So I tried to unscrew it.
(Sorry for crappy phone pic)
Does this have anything to do with a hood (there are lugs on the adapter)? There is a 49mm filter thread on the front as well.