Cultius Ponc wrote:

But now, many companies, Nikon especially, make products using plastic that are just as good if not better than their metal ancestors. Plastic is more flexible and resilient, less prone to expansion and contraction due to heat cycles, doesn't corrode or need special anti-corrosion treatment, and can be easily formed in more comfortable and ergonomic shapes.

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tbcass wrote:

...For example metal expands and contracts a lot more with temperature changes and can get hotter faster which might affect IQ.

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Doug J wrote:

Polymers can be less susceptible to thermal expansion and shrinking.

Let's not get too carried away. Plastics have higher coefficients of expansion than metals.

You guys need to look up a few numbers.  I'm not sure about composites, but bare plastics expand a lot more than metals in general.