A camera obscura, also known as a pinhole camera, is the concept that made modern-day photography possible. Now use the same principal to turn a whole room into a walk-in camera!
Step 1: Find a room Find a room that has a window with a decent view. Look for a blank wall opposite the window, since that's where the picture will be projected. If it's not blank, hang a white sheet on the wall.
Step 2: Create the lens Unscrew the ring from the top of the flashlight and remove the lens. Place the ring in the middle of the sheet of poster board, and cut a hole around it. Then, tape the ring to the cardboard with duct tape. This will be the lens for the camera obscura.
Step 3: Prepare the room Tape the remaining poster board over the window, overlapping if necessary. Leave an area uncovered in the middle of the window for the lens.
Step 4: Add the lens Tape the lens backing to the window with duct tape. The window should now be completely covered, and aside from the lens hole, there should be no light passing through.
Step 5: Darken the room Turn off all lights in the room and close the door so that the only light entering the room is from the camera lens. After a few minutes, your eyes will adjust to the dark, and an image should appear on the wall opposite the window.
TIP: You may need to place a blanket under the door to block out any extra light.
Step 6: View the image You should now see an upside-down image of the outside world projected onto the wall. Why? Since light rays travel in a straight line, they hit the objects outside, pass through the small opening of the lens, and transmit an upside-down image of the objects on the opposite wall. This is the same method cameras use to capture images.
Step 7: Capture your creation Unless you want to cover your entire wall in photographic paper, you'll need a way to capture what you see. Grab a camera with an adjustable exposure setting and set the exposure to around 30 seconds, which is ideal for low-light photographs. Take a moment to marvel at your contraption; it's not every day that you get to walk inside a camera!
FACT: The first digital camera offered to the general public went on sale in 1990, cost $995, and took grayscale photos.