Pinhole Photography Research
What is a pinhole camera: Simply, a pinhole camera is a camera which does not have a lens and only has a single small aperture – hence the name pinhole – thus is a lights proof book with a tiny hole in one of the sides. Light which comes from a screen is passed through the hole and projects an inverted image on the opposite side of the box. Thus the inside is completely dark and is usually painted black. The smaller the hole, the sharper the image will be however it will be dimmer. The optimal size of the aperture would be 1/100 or less than distance the distance between the hole and the projected image. Due to the long exposure required, the shutter can be manually operated with a flap made of lightproof material which covers and uncovers the hole. Exposures can vary between five seconds to a few hours. Solography is the capturing of the movement of the sun over time using a pinhole camera.
To find the optimal diameter of the pinhole can be found using the formula d=. D is the diameter, f is the focal length and λ is the wavelength of light. The depth of field is infinite thus blur is due to the factors such as the distance form the aperture to the film plane, aperture size and the wavelengths rather than the distance from the object. How it works: Light rays reflect off objects and what surrounds us and these form an image on the retina, which the brain then interprets and places the right way round. This is what allows us to see and perceive things. A camera works the same way; it is like a mechanical eye. The ray of light is used when talking about using lenses to form an image. A beam of light is used when discussing making images using a pinhole. A beam of light is a bundle of parallel rays whilst a line of light is a ray of light. Therefore, light can reflect off objects in a multitude of directions, and when a lens is used to produce an image, the rays reflected from the object are reflected to the surface to form a cone of light. As these rays go through the lens they are bent in order to make them disperse then again form a cone. Pinhole images are formed from a beam of light, and the diameter is what dictates the sharpness. The reason is a photograph is made of points of light, if the points are too large then the photograph will not be sharp. This is why a larger pinhole produces a less sharp image than a smaller pinhole. In conclusion, pinhole images are not as sharp as ones made with lens, and the size of the diameter of the pinhole results in softer or sharper images.
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Pinhole photography allows us to a glimpse another universe, another version of our day to day reality Invention of the pinhole camera: The notion of the pinhole camera (a variation of the camera obscura) has been commented on as early as the fifth century BC in Chinese texts discussing the basic optical principles of the pinhole. This was after Chinese writers conducted experiments which led them to discover that lights travels in straight lines. The first person to record the formation of an inverted image using a pinhole was the philosopher Mo Ti, who was aware that light is reflected by objects and that rays that go through the top of the object through a hole will produce the lower part of an image. The next reference to pinhole or camera obscure was in the ninth century AD, in Chinese texts, as Tuan Chheng Shih talks of an image in a pagoda; which he later corrected. Lastly in the tenth century, Yu Chao-Lung used model pagodas in order to produces pinhole images on a screen, but no theory emerged from his work regarding the formation of the image.
In the west, it is Aristotle in fourth century BC who commented on pinhole images asking ‘Why is it that when the sun passes through quadri-laterals, as for instance in wickerwork, it does not produce a figure rectangular in shape but circular? Why is it that an eclipse of the sun, if one looks at it through a sieve or through leaves, such as a plane-tree or other broadleaved tree, or if one joins the fingers of one hand over the fingers of the other, the rays are crescent-shaped where they reach the earth? Is it for the same reason as that when light shines through a rectangular peep-hole, it appears circular in the form of a cone?’. Although not solved immediately, his questions were answered in the 16th century. It is Alhazen, or rather Ibn al-Haytham - Arabian physicist and mathematician- who experimented with image formation in the tenth century AD. His experiment was to place three candles in a row and then have a screen with a small hole put between the candles and the wall. He deduced from his observations, the linearity of light. Over the next centuries the pinhole technique was used to study sunlight projected by a small aperture. Making a pinhole camera: To create a pinhole camera some opt for removing the lens of a DSLR and placing a cap over it with a pinhole. However, it is more interesting to produce a pinhole image by making a box with a pinhole, making the shutter, loading the photo paper and finally taking a picture and developing it. |