You need to check what the values of those border pixels are. Chances are, they are quite low compared to the circular image, and you are only seeing them because of the tone-mapping compression going on in Photosphere, assuming that's what you're using.
From: Rob Guglielmetti <[email protected]>
Date: September 27, 2010 3:04:34 PM PDT
Apologies for the cross posting, just trying to cover the bases.
I have been experimenting with a new camera and Sigma 8mm fisheye lens, creating HDR images for input to Jan Wienold's/Fraunhofer's evalglare program. On the really long exposures, you can actually see the back end of the lens and I guess some of the internals of the camera body itself. While this is exceedingly cool/interesting, I wonder if this is impacting the validity of the HDRs. When I create a Radiance HDR image (-vth) I get these nice round images with totally black corners. With the camera, I end up with a rectangular image and as I said some luminous pixels on the long exposures. Is this a problem, and how do folks deal with this in practice? Even if it's not a problem from an accuracy standpoint, aesthetically it's nice to produce photos that look like the Radiance fisheye output.