Serenar 28mm 3.5 chrome filter thread

[job]

I recently get a chrome 28 3.5 from eBay. Even though all the books and Canon official site quote this lens uses 34mm filter. Mine has no filter thread on the outer chrome ring, but a thread of around 24mm in the inner ring. I cannot find any reference for it.

Anyone get a similar lens

 

[Spavinaw]

I have a Canon Serenar 35mm f3.5 lens with no filter threads. I just have to use 36mm push on filters or a series adapter ring.