Nikon D40 + M42 to K/AR mount adapter + CZ Jena Biotar 58mm f2, originally uploaded by *jj*.
One of my six year olds took this. Full manual. Okay, I preset the f-stop and he danced around until my face was in focus. Nevertheless, he did a good job.
Plunking a M42 lens onto a Nikon is actually fun.
The lens is set at infinity focus. It's actually focused at around 2.6 feet. Judging from the depth of field it was set at f4 or f5.6.