How to remove Pentacon Six adapter from lens?

[CuriousOne]

Hello.

I have mint Kaleinar 3B 150/2.8 in pentacon 6 mount. Couple of years ago, I've bought Sony alpha mount adapter for it, snapped and it worked just fine. Now I got 0.45x speedbooster lens, which I want to use with this lens. But I need to remove adapter first, to be able to install speedboster. The problem is, that adapeter does not comes off! I've tried to rotate it clockwise, counter clowise - it only slides a bit, but won't go anyway. The adapter looks like this:

http://www.ebay.com/itm/Pentacon-Six-6-Kiev-60-to-Sony-A900-A850-A700-A550-A500-/150447012297?pt=US_Lens_Adapters_Mounts_Tubes&hash=item23075739c9

It has small screw on the rotating(?) ring. I've tried to remove it, no luck.

Any ideas?

[ZoneV]

The P6 side looks like the common extension tubes and Kiev/Pentacon camera mount.
So simple rotation of the ring should help. Probably with a bit more force - it could move bad in case some dirt is between ring and mount or barrel.

[Farside]

The P6 adapters have a very shallow screw-on angle and tend to gall.
I've just confirmed what way to get them off, as I keep forgetting that, too.
As you face the lens, you turn the adapter securing ring anti-clockwise.

[CuriousOne]

Ok, I've turned it, but it turns only maybe degree one or two. What's next?

[ZoneV]

Probably more force - but better don´t use the camera to hold against the turning.

[CuriousOne]

I have installed a lens mount from minolta onto large wood piece, made like a huge hex key for minolta lenses

And it helped!

Thanks everyone

[inombrable]

I had the same problem as you. My sonnar 300 P6 had a nikon adapter stuck for about a year, i tried hot, cold and force. How i did take it off, i sprayed wd40 and with a hammer (obviously with as much care as possible) and screw driver hit the adapter anti clockwise, after several hits, the adapter came off and the lens was free.

Good luck with yours.