Principles for a good life

As part of my physics studies, I was exposed to a cool workshop of creating a home camera while learning the first concepts in applied optics: camera obscura, lenses, focal length, etc.

The workshop is presented here for those who want to train students, or just learn about the camera at home.

pleasure is guaranteed!

 

So what is needed?

1. A light-tight box. A wooden box can be printed on a laser printer according to the following pattern (SVG file orDXF file). There is a link to create a box according to other dimensionsHere.

2. A plastic tube with a diameter suitable for the camera (the printed camera is 7.5 cm in diameter). A camera obscura can also be made without the tube, but for the purpose of mounting a lens, it is better to work with a tube.

3. Thick parchment paper, thick aluminum foil, pin

4. Lens. You can order cheap lenses from here. You can experiment with lenses with different focal lengths. 

5. Hot glue and thick adhesive paper

6. A candle, a match and a black garbage bag

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First step - camera obscura

1. If it is a sealed box - cut the back of the box and close the resulting window with thick parchment paper using adhesive paper. Make a really small hole using the pin in the wall opposite to the created screen.

2. If it is a camera printed with a laser printer - assemble the camera and stick with adhesive paper around it. Put the tube in front of the camera and cover it with aluminum foil. Cover the back of the camera with thick parchment paper. Make a very small hole in the aluminum foil.

Now for fun - take a candle and light it, and turn off the light in the room or put the trash bag over your head and over the whole system. Put the camera obscura at a variable distance from the candle and look at the screen on the back of the camera. What You See?

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Second step - a camera with a lens

Remove the aluminum foil from the tube. Glue the lens with hot glue between the two printed circles, and after it has dried, glue the circles to the outer edge of the tube. The back side remains the same. 

The first experiment that can be done is to point the camera towards the window when the light in the room is turned off. This simulates parallel light rays reaching the camera. You should adjust the distance of the lens from the screen in such a way that the image comes out the sharpest. What You See?

Now you can perform a small experiment... See what happens when you bring the lens closer to the screen and when you move it further away? What happens as you get closer to the light source? You can start taking measurements: start from standing very far from the window, let's say, and find the ideal position of the lens so that the image you see on the screen will be clear. Two measurements are made: of the distance of the lens from the window (called U), and of the distance of the lens from the screen (called V). Make some measurements as you get closer to the window, and try to build a graph that links the two sizes (hint: maybe a graph that links one of the U and V parts). From the graph try to find the focus of the lens and compare to what is written on the box of the lens we bought...

Material on the physical theory of a concentric lens can be found Here. 

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