Many of you have wondered why your renderings look noisy or grainy sometimes. Some of you have asked about the difference between Standard quality and Final quality?
Standard quality renderings are meant as draft or preview images. They should be used when you are previewing your rendering and making decisions about colors, materials, textures, camera composition, etc. Typically they render very fast. Also, when you render a 1 megapixel image in standard quality it costs 0 cloud credits. You can iterate over materials and colors in this mode. Once you are happy with the design decisions, you can render in final quality. Rendering a scene requires analyzing all the light sources present, for each pixel in the final image. This calculation is more accurate and also takes much longer. This is meant for the final presentation quality rendering.
An image can also look noisy if there is inadequate illumination in the scene. For example, if you are rendering an interior shot that is lit with sunlight, but do not have enough windows to let the light through, then the image will look grainy. Also, if you are using artificial lights but their intensity is too low, or the number of lights is not enough, then again the image will look grainy. Once you add proper lighting or adjust the sun position, you will see improved results.