The Pinhole Camera

BEFORE YOU START THE EXPERIMENT READ THROUGH THE INSTRUCTIONS

PURPOSE OF THE EXPERIMENT
This experiment is designed to help you understand the working of a simple pinhole camera.

YOU WILL NEED
A pinhole camera, a pin, a lens, some sticky tape and the use of a light bulb (filament lamp).
(A projector is also useful for experiment 4).

EXPERIMENT 1
WHAT TO DO
Collect the pin-hole camera and make a small hole with the pin in the black paper.
Hold the camera about 30cm from the filament lamp and look through the camera at the lamp.
You should see an image of the lamp on the tracing paper screen. Write down what the lamp looks like (you may only be able to see the glowing filament). Is it:
(a) Up side down or the right way up
(b) In colour or black and white
(c) The same size as the lamp itself or not

EXPERIMENT 2
WHAT TO DO
Change the distance of the pin-hole camera from the lamp.
How does this affect:
(a) The size of the image
(b) How clear the image is

EXPERIMENT 3
WHAT TO DO
Make another pinhole about 1cm from the first one
Describe what you see now.



EXPERIMENT 4
WHAT TO DO
Make ONE of the pin-holes bigger using a pencil point.
What affect does it have on:
(a) How bright the image is
(b) How clear the image is
(c) How big the image is

EXPERIMENT 5
WHAT TO DO
Take off the black paper and stick a lens over the hole in the cardboard, INSIDE the box.
Repeat experiments 1 and 2 using the lens.

EXPERIMENT 6
WHAT TO DO
1. Look at the windows through the pin-hole camera especially if it is a sunny day.
2.. Sit someone in the beam of a projector and look at them with the pinhole camera
3. Try lenses with different focal lengths (large or small curvatures).

QUESTIONS
1. Why was the inside of your camera painted black?
2. Why was a light shield used?
3. Why was the image so much better with a lens?

FOLLOW UP TOPICS
1. Try to take an actual photograph with your pin-hole camera
2. Draw ray diagrams to show how the


image is formed on the tracing paper screen.