The exposure on the right the second hand of this wristwatch is frozen at a shutter speed of 1/15 sec. On the left the exposure was 8 sec. I expected the second hand to appear as a blurred smudge but it disappeared altogether without a trace!
Thinking about it, I realized that the perfectly smooth mechanical sweep of the second hand is the cause. A digital clock with its crude sweep of discrete steps give a completely different result http://www.pbase.com/boscodamus/image/88765559

This was shot with the much maligned Pentax K-01 which I got new on the cheap since it was discontinued after only one year of production....i.e. a commercial flop. Still in all it is image-wise equivalent to a K5D and thus capable of a very competitive snap.