Some more experiments here with using a nikon to pk adapter. In addition to the K &F concepts adapter I posted earlier this thread, I also picked up a few other brands.. One I got on Ebay was really a piece of junk, but at $13 dollars I guess its to be expected. I never got to test the optics on this one as when I opened the box and shined a light on the glass it was covered in fungus. Never saw that on something new, but oh well. The seller did not want it, so I decided to pop the glass outand make it into a small extension tube. My thoughts were I would lose infinity but gain some close focus and if I wanted to I could even add some more pentax extension tubes and use some nikon lenses in macro mode...
The results are not too shabby I think. I only tried it on my tamron 200-500 in Nik mount. , same as previous post. The lens is still usable for things like back yard birding. I really am spoiled by AF for Birds though...I'm rusty at best with it on birds.
If anyone has some old nikon Lenses and are shooting Pentax now, I would definitely try to pick up one of the cheapo ebay Nikon PK adapters and pop out the glass... it makes a great Nikon to PK extension tube for about $10-$15 . Its not hard to do at all and you get some extra functionality out of a Nikon lens on your pentax gear. Please note though... the lens needs an aperture ring.
Some shots...
still have a few things to try out and I got in a replacement K &F converter to try again ..
al