Originally posted by creampuff Sorry but talking about legacy lenses is a different context altogether to a modern AF lens, which is frankly quite a lot different construction wise. For one thing, lenses today have to factor in AF. Lens designers have to contend with the size and weight of the focusing ring and focus throw as it has a bearing on the load and inertia the focusing motor has to overcome.
If one were to open up an SDM lens, you will be very surprised to find that the SDM motor is about the size of a button or small coin. My take is some of the SDM lens failures we hear about is probably because early production SDM lenses had not so robust motors. Talking with my local Pentax agent, those lenses that had these SDM issues were sent back to Japan and had their motors replaced with new ones with no subsequent issues arising. One of the early adopter pitfalls.... heck I just recently saw with my own eyes a Sony user's new Sony A900 had its mirror lock up rendering the camera useless... apparently a known issue.
One thing I know is the DA* lenses are pretty solid in build quality, which I can't really say for the DA and some DA Limiteds, the common loose and wobbly lens barrels come to mind.
Sorry to be so obtuse
My entire point is all the gimmicky, electronic motor stuff doesn't change the fact that glass transmits light - that hasn't changed at all.
I find it interesting that we want the durability of a brass and aluminum, lubricated, manually-operated device. Yet we expect that from a device that has nano-wires on circuit boards, motors with self-lubricating, enclosed bearings, machine solders rather than hand-assembly, etc. - and expect it to cost about the same in inflated dollars as a lens did in 1965. All the "improvements" have a cost - loss of durability.
A good 50/1.4 cost about $75 in 1965 - a Spotmatic with kit Super Tak 50/1.4 lens cost $300. The lens would be $506 today. The Kit would be $2,026 today.
A 43 Limited costs around the inflated value of a Super-Tak, and it doesn't have an SDM motor. DA lenses aren't built to last 40 years - to build them that way would be prohibitively expensive.
The problem isn't the lenses - the problem is our expectations of the lenses. If we want a lens that will last 40 years, as the Takumars have, we should be willing to pay $500 just for the durability - then add money for all the improvements, remembering that the improvements also must be durable - therefore expensive. It should be possible to build HyperSonicMotors that would turn a heavy barrel with a long focus throw very quickly - but it isn't possible to build one for the same inflated price as a Super Takumar. Thus we use lighter, less durable parts, small motors, plastic barrels - even plastic mounts - to keep price parity with kits all the way back to the 60's.