This is a commercial Canon video, but it is beautifully made (especially if you click on the youtube logo and select a large size), and it tells a lot of things about how lenses work that few people know. Of course it's not educational in nature, it just flies over the basics.
... BTW, it seems to me that the "ideal lens" would only have one element. But this would require some amazing technology which we surely don't have yet. I wonder when, if ever, we will get that? Perhaps nanotechnology will be involved.
Ol' Ben said...
But Eolake, I doubt you would want to shoot all your pictures in "ideal" light! Since electromagnetic waves of different frequencies follow slightly different paths through the lens, a single lens will ALWAYS show some chromatic aberration (rainbow rings) ... unless you are using a fully monochromatic filter or lighting setup. Black-and-white film/sensors won't fix the problem, since the image is already messed up by the time it gets to the focal plane. You have to have a series of lenses, each one offsetting the aberrations from the others.
I didn't say it had to be a glass lens! :-)
Seems some flourites have almost no Chromatic abberation.
We may one day make a synthetic material which is entirely free of any abberation at all.
Or gather the light with a magnetic field, or what do I know?
Or the "lens" is a 9-molecule thick film consisting of translucent nanobots which working together can make a super fast super-zoom weighing next to nothing. Perhaps it can even enhance the light almost noiselessly, so the entrance pupil can be very small.
That ain't gonna happen this week though!