1) Always when I try to use the KeyShot Depth of Field function I get a grainy result (left image). I would like to have an more smooth/fine blur effect, and I have tried different settings already. So far I can only get the wanted DoF effect by using multiple layers in PhotoShop (right image). Is there a solution to get the same result directly from KeyShot ?
2) Besides this, I have a problem with the floor result. In the left image it ends frayed at the horizon. I would like to have it gradient to invisible (right image). So far I can only get this result with use of PhotoShop. Is there a solution to get the same result directly from KeyShot ?
You can either increase the dof quality under render options, or you can use the realtime rendering (max samples or max time), which may resolve depth of field better for your scene.
Regarding the floor then you may need to increase the ground size (under the environment tab).