Welcome to the world of
Consider the classic technique of photographing a waterfall. The "silky smooth" water effect requires a long exposure—perhaps 1 second or longer. If you leave your ISO at its standard base of 100, and it is a bright sunny day, you might find that even at your smallest aperture (f/22), the image is still overexposed. blur iso
While ISO doesn't cause physical motion blur, high ISO settings introduce or grain. This can give the illusion of a "blurry" or soft image because fine textures and sharp edges are lost under a layer of colored speckles. Welcome to the world of Consider the classic