Supplies to Build a Cardboard
Step-by-Step Instructions With Pictures
The instructions show you how to build a camera obscura out of
cardboard. For your convenience, you can purchase a hobby knife,
a magnifying lens, and 2 sheets of 5-by-6 inch paper vellum for
$10, delivered by U.S. Mail.
The lens has a diameter of 38 mm (1.5 inches) and a focal length
of 100 mm (4 inches). The f-number is f/2.6. It is made of
high-quality glass with smooth edges. The knife is very sharp
and comes with a plastic sheath over the blade. Adult
supervision is required.
To order these items, go to PayPal.com and send $10 to Gray
Chang at this email address:
If you haven't used PayPal before, you'll need to create an
account, which takes a couple of minutes. The payment comes from
your credit card or bank. In the "Add a note" section, specify
your name and address for delivery.
I'll acknowledge your payment and send out the items within 5
business days. The price includes delivery by mail to U. S.
addresses, and taxes where applicable. Sorry, no foreign orders.
You can email me using the address above if you have any
You also need to get the following supplies on your own:
- 1 sheet of cardboard at least 18 by 19 inches
- White glue or wood glue
- 1 brown paper bag
- Scotch tape or packaging tape