Can't figure out what this is. It appears in all telephoto pictures (greater than about 100mm) but not when using my telephoto lenses with other cameras, so it has to be the body causing it. Don't see it in wide angle of mid-range shots. This is the far right 1/3 of the image, so the weird circle of light runs from top to bottom of the picture. Happens on all f/, all shutter speeds, all ISOs, all lighting situations (doesn't matter if it's cloudy, sun is behind/in front/ etc.) I've had some other issues with my D750 lately. Most I've fixed or have resolved over time (lenses not being recognized, shutter "sticking", sensor dust nightmares). But I don't know what's wrong now. I've cleaned the sensor and that didn't do anything. I love this camera but the problems keep cropping up. I've had 0 issues with my D7200.