Also one must allow for the vagaries of human perception - how sharp an image looks on screen or paper viewed from a sensible distance is only very partially dependent on how "sharp" an image "really is" (which is what makes such a nonsense of all the interweb chitchat about lens sharpness and the chimerical "IQ").
If I sent you the negative and you put it on a lightbox under a loupe, you'd immediately find that the sheep are far from "sharp".
This is one of the reasons I get rather oblique in responding to questions like yours and Mark's, and partly why I've stopped by and large from entering into detailed (or, often, any) discussions about the technical aspects of my photographs.
In this case, the most accurate answer to the question "How did you get the sheep so sharp?" is "I didn't"! But that kind of answer is rarely satisfying to the person asking
Since the thread moved towards discussion of general pinhole-ness and included some b/w work, I split it off and removed it from the color image forum. You can find it over here now in the photography technique area.