Is a sphere, the strongest magnifying glass a factory can create?
Cause how can you get more convex than that? I know you could have more spheres infront of it but I'm talking about just one.
36-40, M
ArishMell · 70-79, M
It depends what you mean by "strongest" - magnification or light-gathering power.
A sphere would be a poor shape for a lens because its focal point would be on its surface, and it would probably be very highly astigmatic. The only application I can think of for such a lens is the sunshine-recorder that marks a pro-forma card wrapped around the output side of the glass.
The light-gathering power is a function of its area, hence diameter-squared: a 50mm aperture gathers four times as much light as a 25mm aperture.
The object-lens of telescopes and binoculars is of long focal length, plus the large aperture to image very faint objects. For very powerful astronomical use the object-lens in refracting telescopes, and the corresponding mirror in reflecting ones, are of large diameter and very large radius of curvature, giving plenty of light-gathering and a very long focal-length.
These work by the eyepiece lens of very short focal length magnifying the image produced by the object-lens, by the ratio of their focal lengths. So the larger the difference the greater the magnification.
Hence why telescopic lenses for cameras are so long. Binoculars achieve the same result by folding the long light-path back and forth through prisms.
(I think the mirror on very large telescopes is of parabolic rather than circular profile.)
A sphere would be a poor shape for a lens because its focal point would be on its surface, and it would probably be very highly astigmatic. The only application I can think of for such a lens is the sunshine-recorder that marks a pro-forma card wrapped around the output side of the glass.
The light-gathering power is a function of its area, hence diameter-squared: a 50mm aperture gathers four times as much light as a 25mm aperture.
The object-lens of telescopes and binoculars is of long focal length, plus the large aperture to image very faint objects. For very powerful astronomical use the object-lens in refracting telescopes, and the corresponding mirror in reflecting ones, are of large diameter and very large radius of curvature, giving plenty of light-gathering and a very long focal-length.
These work by the eyepiece lens of very short focal length magnifying the image produced by the object-lens, by the ratio of their focal lengths. So the larger the difference the greater the magnification.
Hence why telescopic lenses for cameras are so long. Binoculars achieve the same result by folding the long light-path back and forth through prisms.
(I think the mirror on very large telescopes is of parabolic rather than circular profile.)
