I'd heard rumors before that Super Takumars (or maybe it was just the 50/1.4?) go yellow sometimes with age, but I always thought the rumor was just a product of people being confused by seeing a yellow lens coating rather than a purple one. But, in the wake of my last 50/1.4 being stolen last spring, I've just got a new one, and looking through it it looks like I've got a yellow filter on the front. So how's that going to effect my photography? Like a yellow filter? Including having to factor in the filter factor, I suppose, as I haven't got a TTL on any of my m42s? Anyone know what exactly causes this little phenomenon?