I've been noticing lately that I had to do a lot of healing of spots that are appearing in the sky on landscape shots which is usually an indicator of a dirty sensor. So for today's challenge I thought I'd take a shot to demonstrate just how dirty my sensor was. This is a color shot of a gray sky with the f stop at 40. Do you think I need to get out the sensor cleaning equipment? :-) That one piece of debris in the upper right looks like a length of rope got in there.