Quite!

Johnha (above) gives us a 1st class link for dealing with this problem
A bit late for me as I used a beer can! I also got a Miranda 70-300 zoom today and found it too had this pesky pin so I dealt with it in my own way by grinding it off .....




It's like real surgery - keep it clean, mask it all except the work area




No more pin ! But the process leaves fine dust everywhere,




so do nothing more until vacuuming it all off




Here's the tell tale PK-A/ Rxxxxxxxx serial number. 'R' = Richo.

Thanks guys!
I didn't have a feeler and I didn't have a razor blade to hand. I did, however, have a beer can which I thought would be thin enough -- and it was.

Here is the culprit (which had engaged on the autofocus screw hole) and the saviour bit of beer can. The AF screw clearly didn't have the oomph to shove it clear but it was far enough to get the shim between the surfaces. I'd tried brute force but, as you can see, the pin is quite robust.

The moral is DON'T USE ANYTHING MARKED "KR", "PK-A/R"; and this one has "(A)P" on the aperture ring.

Unfortunately, I don't have a feeler gauge thin enough but I've tried the others. I can't get a piece of tracing paper in the gap even so. (The screw drive isn't engaged on anything as it's a manual focus). I could kick myself - it actually says KR on it.

I put a Sirius 28mm PKA fit on my K5 without realising it was actually a PK-R fit with that extra Richo pin. I realised I had a problen after less than 1/8th of a turn, when there was a sharp click as this pin engaged the screw hole at the 6o'clock position on the camera mounting ring. Now it will turn either way for a fraction of a turn but it's jammed on solid due to the fouled pin.

Any ideas?

I'm slightly confused here. How big do you want them? And why?
As John says, clicking on them enlarges them - on my monitor, filling the screen.
The only purpose I can see of having monster jobs that need loadsa scrolling to see is so that those with horrendously expensive lenses can show off and compare pixels.

I'll stand corrected if need be.

I've got some in the garden and, believe it or not, they have aphids on them!

You said you were not bothered about having to focus manually. In that case, nearly all the Pentax SMC A and SMC M series are high quality and mainly inexpensive on E bay. Buy it and try it, keep it or ditch it as you will. The Ms are all manual. The As will work with auto settings provided you set the aperture ring to 'A'. It's easy to spot them as their styling is most distinctive. I have one or two auto lenses but I mainly use manuals.

Talking of noises, somebody likes my kind of music I see - Does it sound as good upside down?

That's a relief then! .............. Thank you all ..... and Philip, I shall take the fat white book to bed with me very shortly. You are quite right about the introductory bits getting skipped!