08-07-2011, 10:33 AM
"The edges are what needs "correcting" by stretching them, basically. This leaves the center more or less unaffected. You end up with a larger image, pixel resolution wise. Then you crop this to original pixel resolution."
It seems to me (but I am not sure) that this is not what's happening with the Canon SX220. I have not tried any other cameras. The maximum resolution of the sensor is 12 MP (4000*3000). This is the distorted image. If you now start to correct the distortion, you will have to crop a certain amount of the edges (?) and, consequently, the cropped image will have less than 4000*3000 pixel (can be easily tested if you work with RAW files). If you shoot .jpg the camera nevertheless saves a corrected 4000*3000 pixel image. But this can only be because the image was extrapolated (aka bloated back to the orginal size)? It might be a bit different with a 12MP sensor that can actually record more than 4000*3000 pixel.
It seems to me (but I am not sure) that this is not what's happening with the Canon SX220. I have not tried any other cameras. The maximum resolution of the sensor is 12 MP (4000*3000). This is the distorted image. If you now start to correct the distortion, you will have to crop a certain amount of the edges (?) and, consequently, the cropped image will have less than 4000*3000 pixel (can be easily tested if you work with RAW files). If you shoot .jpg the camera nevertheless saves a corrected 4000*3000 pixel image. But this can only be because the image was extrapolated (aka bloated back to the orginal size)? It might be a bit different with a 12MP sensor that can actually record more than 4000*3000 pixel.