Fogel70 wrote:

The problem is that plastics is often used for making a product lighter and at lower cost.

That can be a good thing for many products...including lenses

From my experience it is plastic parts that most often break,

The only lens I have had break was a metal one. None of my "plastic" lenses have had any issues. It was a metal part that broke (connection to another metal part). In fact...that one lens is the only camera gear I've ever had break in 4 decades

Plastic can work fine if designed carefully, but it seems that in most cases it seems that low cost is prioritized above life length.

Doesn't matter if it's no longer affordable due to higher production/material costs.  If designed well and made using quality materials and production methods...I really see more advantages than disadvantages in the use of modern "plastics" in the production of camera gear.  Pros and Cons with no absolutes

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My opinions are my own and not those of DPR or its administration. They carry no 'special' value (except to me and Lacie of course)