The amount of grains in your images are directly proportional to the ISO setting on your camera. Lower your ISO to lower the amount of grains in your Images. An image shot at ISO 64 will have considerably less grains when compared to images shot at an ISO of 600.
Photography is all about controlling light. The better you control the light the better the image you will produce. On a DSLR camera, light is controlled using 3 parameters.