i wish that canon make all their lenses Plastics even the Super Telephoto lenses
they will be light to carry and cheap to buy
(only the lenses)
You think it's the metal that costs money?
You can buy a kilogram of steel, or aluminum, quite cheaply. And lots of quite advanced metal objects too, designed to a high mechanical precision.
But what do you think it costs to grind the lens elements to the perfect shape, and then put on perfectly even surface coating (often many layers) to avoid reflections? And the glass elements are not without weight either.
Some of the materials of the more advanced lens elements are very hard to work with. And some of the lens elements have very intricate shapes, making them very hard to grind to the required precision. All needed because a prism splits white light in a rainbow and we don't want our lenses to invent rainbows where none can be seen. And we want our lenses to produce a good image with little distortion and good focus all over the image despite the objective having to move a number of lens elements when we change focus. Not to mention the huge shifting around of lens elements when we have a zoom objective.
screw lifted and it's jammed up pretty good. I'm still deciding whether I should fix or replace
