Indeed, I just proved you wrong *more or less*, but not exactly. Of course the photo remains unmatched by my render, although with some more tweaking I may get a bit closer. I must admit that I don't believe that I could create a 100% convincing still image, that would be able to thoroughly fool your eyes for the real thing.
The spot in the middle is the sun, which is not occluded enough by the cloud. I don't know how to fix that other than by immensely increasing the cloud density.
My settings aren't anything special. It's just a tall, 5000 m cloud that comes with a lucky seed. It's important that the sun comes from behind the cloud, so that the clouds appear transparent somewhat. The rest is just finding the right lighting and exposures. You need to have an edge sharpness of 20 or greater and then adjust the density until you are satisfied with the result. Oh, and you need a lot of atmo samples, and high GI settings don't hurt either. This small image rendered over 20 minutes on my i7. Quite long.
Regards;
Frank
