Sensei Rob wrote:

Mako2011 wrote:

Sensei Rob wrote:

Back in the day every manufacturer's top of the line offerings had some type of metal lens barrel, but now everyone makes them out plastic.

Now plastic often out performs metal in many ways.

I'm not sure it does. The trouble with polymers are they're susceptible to UV damage, which, over time, cause them to become brittle. So far as I can tell, this issue hasn't been solved.

Many polymers, and their coatings,  are formulated to resist UV damage and oxidation under near-constant exposure. Window and door frames, car parts including body panels, and outdoor furniture are a few examples.

In terms of strength, even carbonfibre reinforced plastics fall well short of a good steel. They're more scratch resistant, though, I'll give them that.

Polymers can be less susceptible to thermal expansion and shrinking.

it's cheap and lightweight.

That can be a real advantage. Less expensive and not as heavy.

True.

As a hobbyist, I'm after build quality and satisfaction of feel more than out and out performance.

Build quality may have actually improved...though it doesn't feel like that

I dunno. If you look at a good nikkor lens from the pre-ai days, or even a fairly modern one with the crinkle finish (e.g. 28mm f1.4D), they're about as good as build quality gets. Also, I think vintage Leica lenses (like the 50mm summicron dual range) are built better than modern Leica lenses - but they don't count, since they're both metal. I wrote all that just to say I don't think build quality has improved.

An interesting tidbit; early Sony E mount lenses (like the Zeiss collaborations) were made of metal, but the newer ones aren't.

Plastic lens barrels seem somewhat cheap and lack robustness, but they might just be a bit better.

Cheers,
Doug