Because Planck's constant is so small, it's easy to think of Heisenberg's uncertainty principle being relegated to phenomena occurring on too tiny a scale to observe in everyday experience. But there are noticeable effects that show the principle at work.
Photographers take diffraction into account when choosing lens aperture. The smallest aperture settings on most lenses don't give the sharpest pictures because of diffraction. This is an instance of the uncertainty principle: the more the iris confines the position of photons passing through a lens, the less predictable the photons' momentum. In particular, the direction of photons' momentum is uncertain and fewer of them go where you're trying to focus them. Pic from this morning.
Projective test: what do the clouds remind you of?
Mouseover the image for my answer.
photo by Kira Od