Really more useful for landscape and macro photographers who are going to be shooting through very small apertures (f/22 and above), this video from FStoppers explains what diffraction is and how it can affect your shots. The trade off, as they explain in the video, is between a large depth of field and a sharp image; and the trick is to find your “sweet-spot.”
The difference isn’t as obvious on the video even at 1080p, so if you want to see full resolution examples be sure to head over to the original post.
What is Lens Diffraction and When Does Diffraction Happen? [FStoppers]