If you increase the resolution of your measurement of one property, there is an unavoidable cost: you necessarily reduce how accurately you can measure a complementary property....Think about photographing a buzzing fly. If your shutter speed is high, you'll get a sharp image that records the fly's location at the moment you snapped the picture. But because the photo is crisp, the fly appears motionless; the image gives no information about they fly's speed. If you set your shutter speed low, the resulting blurry image will convey something of they fly's motion, but because of that blurriness it also provides an imprecise measurement of the fly's location. You can't take a photo that gives sharp information about position and speed simultaneously.
From page thirty-one of Greene's Hidden Reality, a book doing an excellent job making the complex understandable.