Originally posted by pacerr Pentax COULD design and produce bodies such that each incremental manufacturing tolerance was miniscule and each unit had a custom, hand-fitted VF shim to accommodate residual assembly variations -- and they COULD replace all tooling weekly to maintain perfect tolerances and QA goals -- and they COULD conduct 100% QA sampling -- and those of us with a Rolls Royce with driver and a gold Rolex or three could maybe afford 'em.
Pentax used to produce cameras where the principals of Deming's teachings were applied and continuous improvement was the rule. Now days, the mantra is "good enough for the intended purpose" and the intended purpose is AF with a slight nod being given to non-AF use cases. Pity that the AF systems are poorly suited for fine focus.
Note that I reference the past both in this post and the one you quoted. The tolerances for the mirror box used to be sufficiently close that shimming was the exception rather than the rule. It was expected that the end user would be able to swap the screens on the Pentax MX without having to check the calibration against the focal plane. Proper manufacture of the mirror box and light path is not rocket science, it is simply not a current priority.
Those vintage cameras were mass produced, though with human labor rather than robotics. I own multiple film bodies (Pentax, Ricoh, and Minolta) and the viewfinders on each are spot on despite being built using manual processes.
Yes, I hear whistling with those old bodies and it is excellent whistling, but there is no pig in sight. With my modern AF dSLRs, they only whistle if prodded and massaged because whistling was not in their design spec.
Steve