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[-] Triumph@fedia.io 77 points 2 months ago

The reason this happens is because the tiny gaps between the leaves act as lenses, like in a pinhole camera.

[-] Wolf314159@startrek.website 22 points 2 months ago* (last edited 2 months ago)

A pinhole camera has no lens. The effect here is like a pinhole camera, but a pinhole camera is nothing at all like a lens. Pinholes diffract light. Lens refract light.

EDIT: Of course you can't resolve an image through diffraction. That's not how pinholes cameras work. Diffraction negatively impacts image resolution, but it absolutely happens when light passes through them. But, although lens do use refraction to resolve an image, that same process also has unintended negative effects on image resolution (spherical aberration, chromatic aberration, etc.). I didn't bring up any of that because it was ultimately a distraction from the important part: narrow gaps diffract light, lens refract light, and pinhole cameras do not work like lens.

[-] Quibblekrust@thelemmy.club 10 points 2 months ago

Pinholes diffract light.

The diffraction effects from a pinhole camera are not what make them work. In fact, diffraction makes the photographs worse than they otherwise would be. The pinhole makes an effective aperture for photography because it's small size produces small circles of confusion on the film plane. Ideally, you would make the hole as small as possible, but beyond a certain (small) size, defraction becomes the dominant source of blurring. So the size of the pinhole should be chosen to yield the best balance between geometric blur and diffraction blur.

The diffraction is merely a limit to the smallness of the aperture, and not what creates the image.

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[-] Opisek@piefed.blahaj.zone 3 points 2 months ago

Our window blinds at school had tiny holes in them for the strings to go through and they had the exact same effect. You could see the eclipse projected once the tables.

[-] baltakatei@sopuli.xyz 33 points 2 months ago

Sunlight is always doing this. It's just that we call overlapping projections of a boring white-filled circles “dappled sunlight”.

[-] ameancow@lemmy.world 20 points 2 months ago

Additionally, if you can make sunlight shine through a tiny hole that is somewhat level with the ground into a dark room or box, onto a flat, white surface, you can often see a projection of the world outside if the sun is hitting everything just right, the image will be upside-down and reversed, but often in full color like a video image.

Naturally occuring camera obscura must have freaked people the fuck out in olden times.

[-] HeyThisIsntTheYMCA@lemmy.world 11 points 2 months ago

in the house i grew up in, when the blinds were down in my window i would have a camera obscura for like half an hour each day. it made sick days more tolerable.

[-] ChanchoManco@lemmy.zip 7 points 2 months ago

Once I hitched a ride on the back of a empty meat truck, so it was pitch black, some minutes in my eyes got used to the dark and started to notice a projection on the front wall and I could somewhat see what was behind the truck, even got to id car models.

[-] mEEGal@lemmy.world 23 points 2 months ago

You can actually use this, or more generally the shadow of a tree on any sunny day to calculate the distance to the sun !

(Can't seem to find the video demonstrating it, but I have a feeling it's from Physics Girl or Up And Atom on youtube)

[-] Wolf314159@startrek.website 10 points 2 months ago

The ratio of the size of the image to the distance from the pinhole is the same as the ratio of the size of the sun to the distance to the sun.

[-] Quibblekrust@thelemmy.club 5 points 2 months ago

Only if you know the sun's size, which kind of presupposes you know its distance.

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[-] Zkuld@lemmy.world 4 points 2 months ago
[-] mEEGal@lemmy.world 4 points 2 months ago

My gut says Thales' thorem, but this needs checking.

That's why I was looking for the video

[-] mmmac@lemmy.zip 1 points 2 months ago

shadow length = object height / tan(sun elevation angle)

Some basic trig

[-] Akasazh@feddit.nl 16 points 2 months ago

It's uncanny and special for someone to be looking the other way during an eclipse.

It's so short and a rare enough even that would make earth a tourist hotspot for extraterrestrials if there ever was interplanetary tourism.

[-] Trainguyrom@reddthat.com 11 points 2 months ago

It’s uncanny and special for someone to be looking the other way during an eclipse.

During the two minutes of totality I tried really hard to take in as much as I possibly could. The light was very weird the entire time and because I wasn't looking at the sun and moon when it happened, I saw the weird wavey shadow things as totality ended. Absolutely incredible experience and I highly recommend everyone experience it at least once in their life!

[-] InputZero@lemmy.world 7 points 2 months ago

Unless it was an annular eclipse, or it was a total eclipse and they weren't in the path of totality. Then this is all they would see. Regardless without eclipse glasses you shouldn't look at either eclipse at all.

[-] Akasazh@feddit.nl 2 points 2 months ago

I witnessed a partial one, with eclipse glasses. Still I didn't have the time or observational talent to notice the effect on the shadows

[-] Buddahriffic@lemmy.world 2 points 2 months ago

You can glance at the sun but don't stare at it. Even when it's only 1% visible, it's putting out enough light to strain or damage your eyes.

Though it's fine to look at the eclipse with naked eyes when it's total. You can't really see the cool effect surrounding the moon during totality with the eclipse glasses on because it's way dimmer than the sun usually is.

Your eyes will tell you if it's safe to look. If it's uncomfortably bright, then you shouldn't power through that discomfort (and that applies to things other than the sun). If it feels like looking at anything else, then it's probably fine.

[-] Hathaway@lemmy.zip 1 points 2 months ago

Or they had a camera recording.

[-] gmtom@lemmy.world 4 points 2 months ago

You only see this during the partial stage of the eclipse, not during totality, which can last a long time.

[-] Akasazh@feddit.nl 1 points 2 months ago

I witnessed a partial eclipse, didn't notice the shadow effect. I might pay attention next time...

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[-] gmtom@lemmy.world 13 points 2 months ago

Picture I took in Texas during the eclipse

[-] joshthewaster@lemmy.world 16 points 2 months ago

Here is one I took using our hands to create the effect.

[-] stochastic_parrot@sh.itjust.works 5 points 2 months ago

I'm having a hard time understanding this. How many hands do you have? How can you use 2 hands to create this effect and still hold a camera?

[-] TheOakTree@lemmy.zip 8 points 2 months ago

They said our hands. Clearly they are a conjoined twin with 3+ arms.

[-] joshthewaster@lemmy.world 4 points 2 months ago
[-] pyre@lemmy.world 7 points 2 months ago

we're not going through this again

[-] supersquirrel@sopuli.xyz 4 points 2 months ago

why? They clearly have crab claws for hands, how else would that picture be possible.

[-] tipicaldik@lemmy.world 12 points 2 months ago

We have LED street lights and our driveway is lined with crepe myrtles. Every evening after dark, I can see the grid pattern of the individual LEDs in the shadows on our driveway. It's trippy when there's a slight breeze, and all these little "grid shadows" are moving around overlapping each other

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[-] MasterOKhan@lemmy.ca 8 points 2 months ago

Best bokeh balls

[-] latenightnoir@lemmy.blahaj.zone 7 points 2 months ago
[-] ivanafterall@lemmy.world 1 points 2 months ago

Heey, it's the intro to Heroes on NBC

[-] tdawg@lemmy.world 6 points 2 months ago

Thought it was just my coffee table

[-] justlemmyin@lemmy.world 5 points 2 months ago

well technically thats shadow of moon multiplied "naturally".

[-] Kolanaki@pawb.social 4 points 2 months ago
[-] supersquirrel@sopuli.xyz 4 points 2 months ago

I think you need to turn on antialiasing in your settings

[-] untorquer@lemmy.world 3 points 2 months ago

Reminds me of a few Cessna's i worked on.

[-] webp@mander.xyz 2 points 2 months ago

Big if true

[-] HakunaHafada@lemmy.dbzer0.com 2 points 2 months ago
[-] buttnugget@lemmy.world 2 points 2 months ago
[-] JoShmoe@ani.social 1 points 2 months ago
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this post was submitted on 09 Oct 2025
980 points (99.0% liked)

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