Quote: how can you tell it suffers from barelling?
If you rotate the image to try to get a 'flat' horizon you will see that the horizon is curved - in this case as it is towards the bottom of the frame and curving down in the middle there is barrel distortion. If the curve was upwards it would have pincushion distortion. HTH.
-------------------- Steve Thompson FRIPN
Benches - for togs who really know where their towel is.