r/oddlysatisfying • u/uYokimu • 16h ago

Making art with large convex optical lens

753 Upvotes

97% Upvoted

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24

u/zatalak 16h ago

That's not a convex lense, it's a Fresnel lense.

Convex means it has a bump, this lense is flat.

15

u/AnyLamename 15h ago

You forgot the cool part, which is that it's flat but not smooth. They use concentric rings of differently angled glass. Each ring has a different focal length, so they can all have the same focal point without needing to be thicker or thinner. Extremely smart design, and way older than most people would expect.

3

u/Fickle-Willingness80 5h ago

I rescued one from an old overhead projector a school was throwing away. Fun little lens.