SMC coating colours.

mowog · 2010-07-05T19:17:12+0100

I have two identical Pentax lenses. SMC-M 135mm f3.5s. Excellent, compact teles, much discussed and admired, on this forum. Identical, except for the coating colour, that is! One has a purple tint, to the front element. I thought they all had. I have had a few pass through my hands over the years, and as far as I recall, they were all purple. The second I have now, is green!. A lovely deep emerald green tint. I was careful to hold both lenses up to the light at the same angle, and position. The second one is without doubt, green. :shock: I never noticed, until I had them side by side, today. Has anyone else noticed this, in other Pentax lenses? . Maybe Asahi changed the coating recipe for a while, like Coca-Cola famously (and disasterously) did, a few years ago.