I am the proud owner of a D500 and the performance so far is astounding. As with any new camera, there are a lot of nuances that need to be learned in order to get the most satisfying performance. For those owners of the D500, how high do you set the auto ISO? I find the noise control to be very good overall and I know the camera can shoot up to 25600 iso but do any or you have a number you find acceptable on the high end of the auto iso? Eventually I will figure out the level I find acceptable but a little information from current users might be helpful.