Quote Originally Posted by Paul_Baker
Check this page out. It shows the darkening of the corners at 1.4 very clearly.

This is exactly what is happening. As long as it's not something wrong with my lens, then I'm fine with it.

I can appreciate your advice. I will use it to my advantage and at least I know now that I can stop down to lose the effect. I've taken some great shots wide open with this lens, that wouldn't have been possible had I not had the extra stop.

Thanks to everyone,