While looking through my a700's viewfinder at bright, sunny landscapes in Alaska--such as glaciers--I sometimes saw what appeared to be a split screen. The left half of the viewfinder screen looked sunny and blueish while the right half of the screen looked overcast and cold. It was almost like I was using a split filter with the split used vertically right down the middle instead of horizontally. I thought at first that this was being caused by my circular polarizer, but the same thing happened when I used a UV filter instead of the polarizer. This only appeared when looking through the viewfinder and did not appear to affect the images. I can't recall whether it happened only with my Sony 18-250 lens or also with my Minolta 100-400 APO. Has anyone else experienced this effect? Does anyone know what causes it? Might it have anything to do with the prescription sunglasses I was wearing?

Andy