Pentax shake reduction with long lenses

I read a few times that the in body shake reduction is less effective for longer focal lengths. I own an old Tokina-ATX 400mm AF lens and a K10D and wondered how effective it would be. So I did a quick test, three hand held shots at 1/15s, ie 5 stops below 1/600s.

Result: good, moderate, decent

and with SR off: bad, bad, bad

Conclusions, even with my old trusty K10D a very decent result!

First the three SR images, followed by 3 without SR: