I'm glad to see that this thread has been getting a workout over the weekend. Good info and links everyone, thanks for participating. Hot spots can be an annoying problem. John's suggestion is good, but also experiment with the f/stop you are using. I can't recall at the moment, but either stopping down or up should minimize the hotspot. I THINK the wider the aperture, the less pronounced it is, but don't quote me on that. I have also hear that certain filters are more prone to it as well, specifically the R72s. The filters that block out more even more light are less prone to the hotspot effect. It is a little difficult to describe, but I minimize the hot spot I get using my C8080 and R72 filter by using the circular selection tool to select most of the photo, then feather 250 pixels and bring up either the darks or lights using levels to compensate. Then I select a smaller central circle and do the same thing until the image has evened out a bit.

Kort Kramer - Kramer Kreations