Please advise on manual macro lens

Hello

I am looking to add a macro lens to my kit.

Manual is my preferred choice and it can be PK or M42 as I have an adapter.

I use a K-R.

My subjects are likely to be "found" items and general portrait use. Not big on nature!

Many thanks
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http://www.pentaxphotogallery.com/artists/mac68
http://www.flickr.com/photos/simac/