Originally posted by Cipher It was common knowledge in the 70s, which is why the lens was discontinued. After mine failed, (and I had it set up properly) I brought it in and had the leaf shutter disabled. The tech told me that it was a flawed design. It was true for me, and I found out the hard way.
Both the 90mm LS and the 165mm LS were made up to 1989 and included in the revised SMC Pentax 67-designated lens line-up.
On both lenses the leaf shutter is recommended to be held in the
relaxed (springs closed) state when they are not used for some time. This is the only known precaution I am aware of that could affect reliability over the very long term. Maybe your early lens was fatigued. LS lenses of that earlier generation are still available in the used market, and many still would have seen heavy professional (studio) use.
Last edited by Silent Street; 06-25-2018 at 09:37 PM.