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New Take On The Camera Obscura Brings Paris Indoors | Hackaday

We haven’t checked, but we’ll go out on a limb here and say this is the first project we’ve featured with a BOM that includes “an apartment in Paris with a breathtaking view of the Eiffel Tower.” We suppose there are other places in the world where a giant camera obscura like this would work too, but you’ve got to admit that the view is pretty spectacular.

Of course, a camera obscura is really just a dark room — that’s literally what it means in Latin — with a small aperture to admit light from the outside world. This projects an inverted image on the opposite wall, which must have looked absolutely magical to pre-technical people and honestly is still pretty stunning today. Either way, it’s a low-tech way of seeing the world in a different light. [Mathieu Stern] decided his camera obscura would turn the traditional design on its head. Literally — he wanted an upright image. Luckily, he found a supplier that makes special optics for camera obscura that do just that. It looks like the optic uses a Dove prism to invert the image, or in this case to turn it back into an upright image. M5.5 Lens Holder

New Take On The Camera Obscura Brings Paris Indoors | Hackaday

The real hack here was finding the perfect place with just the right view of the Eiffel Tower — not at all an easy task in a medieval city where streets go where they will and buildings tend to block the sightlines. [Mathieu] eventually managed to find just the right place. With a little aluminum foil to make the rented room really obscura and some strategically positioned sheets to improve the projection surface, he was able to project some beautiful images of the landmark and surrounding cityscape in a panorama on the apartment walls. The video below has some stills and time-lapse sequences that are pretty breathtaking.

We’ve seen other camera obscura before, including this mobile version which may have made things easier for [Mathieu], at the price of giving up a lot of the charm.

See also https://youtu.be/AIVH6LmBvt4?t=125

I love Paris, I visit it 2-3 times per year. My gave with myself is to nót see the Eiffel tower, which I surprisingly often manage. I think the only time I had a room with a view to the Eiffel tower, was when I was in Issy-les-Moulineux, a community outside the Paris département

I did six two-week stays in Paris a few years ago.

EVERY SINGLE TIME, the Hyatt Regency Étoile gave me a room with a view of the tower.

I guess giving them a commitment of 12 weeks of hotel stay makes them want you to have the tourist room experience.

I live in an attic apartment in the French Quarter, NOLA. Its very hot in the summer because the builing is ~200 years old and was designed for open windows airing out during the heat. Instead the lower tenants blast AC which pushes their apartments heat into the stairwell, and UP UP UP to my home. Our AC runs 24/7/52.

The point of all this? We foiled over all the windows the first summer. It was the only way to get the apartment to drop below 80F(27C). As the sun rises in the east and climbs in the sky, Light batters my building, Blasts my windows, is thwarted by the aluminum foil. Until one morning, having peeked out the window by pulling the foil back the night before, a single beam of light penetrated my shields and the darkness of my sleeping chamber,….

And there on the wall, as clear as a painting, hung upside down, was an image of the roof spires of the Cathedral. My room had accidentally became a camera however obscure a thing that was.

That is a charming story that I can “see” in my mind’s eye…the ultimate “camera obscura.” Thanks for sharing that.

I live next to a subway line. Sometimes I leave a sliver between the curtains and I can see them drive past on the ceiling. I love that!

Maybe also run a dehumidifier. Dryer warm air doesn’t “feel” as hot as the average humidity in NOLA. I’ve visited in June. I have no idea how you make it through July and August there.

Tucson hosts an international Gem and Mineral each year. One day, while examining the wares of one of a thousand vendors, I came upon a guy with a table covered with Rubbermade totes. In each tote where piles of crystal-ball-sized polished quartz spheres. As I looked more closely, I noticed dozens of arch-shaped burns in walls of the totes. As the sun swept overhead, the spheres focused the sunlight into pin dots of light that left charred records of the sun’s movement into the plastic.

I have also heard of a medieval “alarm clock” that was basically a kind of sundial with a lens in the gnomon. At the “12 noon” position was a small brass cannon with a flashpan of power that could be ignited by the sun. The cannon’s report could be heard for miles. Presumably this would call field hands and other workers in for lunch.

This makes me wonder… Is there any scenario (sun directly in the image and a window curtain, bed sheet, or human walking into the projection field) where the obscura lens could set something on fire?

With a traditional pinhole camera, the pinhole itself is the point where the light rays cross, so that’s the point with the greatest energy density… at the surface of the projected image, the same energy is spread over a greater area, so the heat absorbed per unit area is lower. Even in flipping the image, the greatest intensity is at one of those crossing points, in which the image will be too small to see. So just in a general sense, I would say that if the image is large enough to see from a distance, then everything is safe…

But you do have a point since this is a very long-duration projection. If somebody had a pinhole followed by a convex lens to invert the image beyond the pinhole, and then pulled a curtain closed and it would happen to be at the lens’ focal point, in enough sunlight it would be just like trying to intentionally start a fire with a magnifying glass.

Then again, the area of the pinhole is so small that it does not receive a large total energy, and that is the full amount of energy that can be passed through.

pinholes generally speaking have orifices sized in fractions of millimetres in photography. Judging from how blurry this image was, the opening probably was measured in tens of mm. Assuming the orifice was 30 millimetres, the energy density for paris would be roughly 0.0763 W/cm2. In other words, harmless.

Oohhh. I was hoping that Matthieu was making large contact prints directly from the Projection. And that it we’re possible top buy Limited prints from the Project. Maybe in his new projects.

That is pretty amazing. I’ve always wanted to black out my windows and project a view onto my wall

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New Take On The Camera Obscura Brings Paris Indoors | Hackaday

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