Shows how lens aperture controls depth of field — the range of distances that appear in focus simultaneously. Students see the trade-off between light gathering (wide aperture) and depth of …
Demonstrates how aperture size controls depth of focus. Students observe that reducing the aperture of a camera allows pinholes to remain in focus over a wider range of image-plane positions, …
Students observe that a simple plano-convex lens cannot simultaneously focus red and blue light, demonstrating chromatic aberration from wavelength-dependent refraction. Comparing with an achromatic projection lens shows how doublet designs …
Demonstrates chromatic aberration in the human eye. Students observe a purple halo around a UV lamp that they cannot bring into sharp focus simultaneously with the blue tube — direct …
Shows that rays passing through outer zones of a lens or mirror focus at different distances than paraxial rays — spherical aberration. Students see that the thin-lens equation is an …
Demonstrates how refractive index contrast at interfaces determines optical behavior. Dry glass spheres appear opaque due to multiple glass-air reflections; adding water reduces the index mismatch, making the spheres nearly …
Air-filled lenses submerged in water reverse the expected behavior: convex shapes diverge light and concave shapes converge it. Students see directly that lens action depends on the refractive index contrast …
A water-filled spherical globe magnifies a suspended marble in air, but the magnification nearly vanishes when the globe is submerged in water. Students see directly that lensing power depends on …
Show how Fresnel lenses use concentric grooves to achieve the focusing power of a conventional thick lens with drastically reduced thickness and weight. Students examine the groove structure and verify …
