| Now, when you think about a camera, |
| you probably think the most important feature of a camera is the lense, |
| but back then there was no lense. |
| So the camera must use different type of technology to take pictures. |
| The very first "camera" makes use of a pinhole to project the image |
| but the resulting projection was upside down. |
| Because it makes uses of a pinhole, it is known as pinhole camera. |
| So. as I just said, |
| a pinhole camera is a simple camera without a lens |
| and with a single small pinhole.... |
| It really is just a light-proof box with a small hole in one side. |
| Light from a scene passes through this single point |
| and projects an inverted image on the opposite side of the box. |
| Because a pinhole camera requires a lengthy exposure, |
| its shutter may be manually operated, as with a flap made of light-proof material to cover and uncover the pinhole. |
| Typical exposures range from 5 seconds to several hours. |
| Can you really imagine having to wait hours for a picture? |
| It seems so strange now considering we can snap a picture and see it immediately in a screen at the back of a digital camera.... |
| Let's be real for a minute, |
| with the long exposure time and our fast paced world, |
| is there really a need for these types of cameras?.... |
| The answer is yes, and this is why... |
| the most common use of the pinhole camera is to capture the movement of the sun over a long period of time... |
| and this type of photography is called solargraphy. |
| The image may be projected onto a translucent screen for real-time viewing |
| which is popular for observing solar eclipses, |
| that way you are not harming your retinas looking directly at the sun..... |
| Or, to be a bit more technical... |
| Pinhole devices provide safety for the eyes when viewing solar eclipses |
| because the event is observed indirectly. |
| The diminished intensity of the pinhole image being harmless compared with the full glare of the Sun itself. |
| Okay! |
| So we know a few more things about this camera, |
| but where did it start? |
| As in who created this neat little contraption? |
| Ibn al-Haytham, way back in the 10th century |
| wrote about naturally-occurring rudimentary pinhole cameras. |
| For example, light may travel through the slits of wicker baskets |
| or the crossing of tree leaves..... |
| If you think about it, the circular dapples on a forest floor, actually pinhole images of the sun, |
| can be seen to have a bite taken out of them during partial solar eclipses |
| opposite to the position of the moon's actual occultation of the sun |
| because of the inverting effect of pinhole lenses... |
| It's neat, right? |
| A natural pinhole camera, indeed. |
| Alhazen published this idea in the Book of Optics in 1021 AD. |
| He improved on the camera after realizing that the smaller the pinhole, |
| the sharper the image, though the less light. |
| He provides the first clear description for construction of a camera obscura...... |
| So next April, when World Pinhole Day is held on the last Sunday, |
| you can tell people exactly why it is being celebrated. |
| Today we are going to discuss a camera |
| that you can not only make from virtually anything but it actually works.... |
| Sounds a little crazy I am sure, but relax |
| and let's take a peek into the world of pinhole cameras..... |
| A pinhole camera really is one of the simplest ways to get involved with and enjoy photography. |
| The pinhole camera has existed for more than 500 years |
| and may even have its place in ancient history.... |
| Totally different from the cameras we use today, |
| it requires no lenses. |
| Pinhole cameras are also a great way to introduce little kids to the joy of photography and the basics of optics. |