Originally posted by reh321 If a lens lasts "only" ten years, I would consider it to be a real success, especially at my current age of 73.
There may be a whole new set of motors in ten years - perhaps even a "KAF5" mount - we should not take a 'glass is forever' approach here.
I think "glass is forever" hasn't been a truism for most lenses for a very long time... if it ever really was...
M42 was ~20 years for Pentax, "K" was another 20, "KAF" was another 40 or so, and now the "KAF4" era starting a few years ago, where the prior generation loses significant functionality compared to the newest...
And yes, I lumped KA into "K"; and KAF2, KAF3 into "KAF", which is sloppy... and subject to very many different interpretations...
Canon had even more of a break, though EF has had close to 40 years.
I think of my F35-70... great little lens, but it's obvious it was not designed to be around 40 years after its manufacture...
-Eric