Hello all, I woke up this morning to take some pictures at different exposures. I am using photomatix to make some neat HDR and tone mapped images. Now my question is that I am getting a dark cirlce in the top left corner of every image. I don't see it in the raw, but after I generate and HDR image and tonemapp it, I can see this dark circle in the same spot of every image. Now I could clone stamp it out, but I would like to know how to get rid of it all together. I am using a new Nikon D80 and new lens. I thought it might be something on the sensor, but it is not a spec, but a cirlce. Thanks for the help.