I took the attached shot with a 5DII 24-105L lens, at F4 105mm. I kick myself for shooting at F4, it was a mistake when I inadvertently switched from manual to aperture priority. It was way below zero up here so I can forgive myself for making this mistake. I took the shot on RAW and the picture you´re looking at was converted to Jpeg via ACR.
Firstly there´s dreadful banding in the sky, a problem I´ve had with a number of recent shots taken with that lens, at different apertures.
I´ve some ideas what may be causing it but I´d like to hear other folks opinion.
Also why am I getting such bad light fall off at the corners. I thought the 5DII corrects for this with its CORRECT FOR PERIPHERAL ILLUMINATION.
Unfortunately I am traveling in South America without a computer (internet cafe here). I´m hoping my lens isn´t faulty because the 24-105 gets the most use and I am only part way through my travels.