A fruitful source of candids is those people who are so engrossed in what they are doing that they don't notice you taking aim. Typical activities are eating, finding the right track on their mp3 players (they can't hear you approach either!), chastising children/dogs/partners (ditto) and taking photographs.
This lady is engrossed in trying to take a portrait of her shadow, in bright sunlight (remember that?) in the courtyard of Krakow's Wawel Castle. You may by now have recognised mrswoolybill, still cracking on with my old Olympus. And if you remember my comments on glassware uploaded yesterday, it's that lens again!
55mm, 1/250th sec @ f16
Sorry about the background - tried to clone it out, just made it worse. But it was there.
Never did find out what the portrait looked like!