How to make a small camera obscura with your own hands?
I made from landscape cardboard.
We mark one sheet to get a square tube, e is equal to the short side of the sheet. We glue.
On the second sheet along the length we mark a strip with the width of that pipe minus 3-4 mm, leaving space on the sides. On one side of this strip, mark a square. This part will be the back wall of the pinhole camera. Not on three sides allowances of one and a half cm, which will have to be bent in the future, on the fourth side - the same strip, e, too, must be bent. It will not be possible to move the back wall around the chamber. In the square part, a window is cut out almost to the entire wall in size (if only the cardboard does not break), tracing paper is glued into it.
The third detail is the front wall. We make a square from the third sheet, which could be used to close the pipe. Pierce a hole in the middle with a sharp needle. We glue it to the pipe so that there are no cracks on the sides.
Now it would be good to fill this pipe with internal paint from the inside. For example, from a cylinder. And fix the hole in the front wall.
Behind the tube insert the thing with a screen of tracing paper. We direct the device with a wall with a hole in space, we look inside on the other side.
But what is there to do? Everything is as easy as shelling pears. Take a box, for example, cardboard, not flat, it will not work from sweets, but with approximately equal length, width and height, bulk, that is. Inside, we paint it in black color - with a marker, paint, or simply paste over all walls with black paper, except for the back. We remove the back wall and instead of constructing a screen - we tighten it with a thin matte white film or paper. Very thin to see through.
In the front wall, we "build" a "lens" - just pierce a tiny hole in the center - with a needle or an awl. Sun! Camera Obscura - Ready! We go out with her on the street and observe on the improvised screen a moving (but inverted!) Image of everything our improvised lens is directed at. The brighter, the sunnier the day, the brighter the image on the "screen".