Any idea how to open this brass lens?

[erian]

I want to access the back of the front group of this lens.

192232
192233

So far I have no any idea how to open it.

Is there an easy way to it or should I expect to put it in a vice?

[RedGreenBlue]

It looks like the front cell, or element, is held in place by that thin black ring. I don't see spanner slots or holes in the ring. My suggestion is to grip the ring with a rubber tool and turn it out of the brass threaded cylinder. It won't be easy to fashion a rubber ring or tool that will fit the retaining ring and not rub the glass, but it should be doable.

Scott

[Greg]

Those 3 holes in the front hood? of the lens might be the key... have come across another lens with 2 holes in the front. Front could be unscrewed by placing a metal rod through the 2 holes and rotating it.