Now thats a great lens! Is that a M42 mount? how are you adapting it?
Marc
Pentax mount is probably the most versatile mount in today's dlsrs. (except the micro 4/3 but they aren't dslrs)
You can mount almost everything and keeping the A mode in many series. M42 adapters abund in ebay but genuine ones are difficult to find.
There are a few russian exact copies of the genuine Pentax adapter that are better than the chinese cheap replicas.
If you use a genuine or russian copy, you won't need tool to remove the adapter and your lenses will have the engraved indications aligned on the top where they should be. Chinese versions will work but
you'll need a tool (provide with) and you aren't sure your lens indications will be aligned. If you can't have infinity focus, a little peice of aluminium paper and you're done.
Beware of the Ricoh or Pentaflex, KR bayonet because they are Pentax mount compatible but have a little additional contact that can be very problematic if you do not know the right procedure and wich one has to be removed. You'd have issues to take-off the lens. If it happens, don't force anything, just switch several time your MF-AF button while turning gently the lens but the best is just avoid them. (and they aren't good optics anyway)
Using M42 you are totally manual, it's good for a slow style of photography but remember that you actually see in the viewfinder your real aperture wich is difficult to focus if you stop-down but with live-view...things are simple.
M42 Pentax (and non Pentax) line IMO are highly recommended but use them with a good lens hood.
You can also mount old Pentax MF lenses with superb results.
http://shop.ebay.com/i.html?_nkw=pentax+6x7+to+K+adapter&_sacat=0&_odkw=industar+26+m&_osacat=0&_trksid=p3286.c0.m270.l1313