Between pixel density, and resolution. I ask because I've been told that the greater the pixel density the greater the ability a sensor has to resolve fine detail. That would appear on it's face not to be true, since a Nikon D810 has more resolving power than a Nikon D7200, which has greater pixel density, and by a fair amount. If the D7200 for example were scaled up to a full frame, it would have roughly 50 mps density wise. We need this issue resolved once, and for all, because the effect of it appears to be that nobody knows nothing.