Thanks for the vote of confidence in this lens. Info has been hard to find, but the current owner assures me it has an auto diaphragm, and I have now got some lovely Elicar auto-bellows, so I mean to go ahead and make the purchase.
I previously made the mistake of buying the modern DA 100mm autofocus macro lens, and although its a perfectly OK lens, I would have been better getting the old manual focus. I dont much like auto-focus, having never had it before. It don't seem to be able to focus as critically as I would by eye, so what's the benefit, besides speed in situations where speed is important. Not macro, or landscape work, which I prefer to do. Oh dear, I'm ranting. Must be old age.