Photoshop Video Tutorial - Finding Shadows and Highlights with Levels

So we know what shadows and highlights are, and we also know a way of locating and using them in conjunction with the relevant eyedroppers - but surely there must be a more accurate way of finding the brightest and darkest pixels inside an image? Well I'm glad you asked, as with assistance from the threshold command, the colour sampler tool, the info palette and the eyedroppers we can achieve pinpoint accuracy in a modest amount of time.