Anybody know what the deal is with some of the G lenses when it comes to coatings? I've had 2 45's with a reddish hue over the rear element--and I'd swear that this warmed up highlights on me. Same with a 28 and a 35. 28 I'm currently using has no reddish hue, but is more neutral. Once on e-bay, I saw a 28 being sold and a remark that it was one of the ones with the reddish coating. Anybody have any idea about this?