Pinhole Camera
In this project, we built a pinhole camera in a box of size 36cmx32cmx23cm, by covering the box with black paper and using 2 sheets of white paper to act as the screen. We used a Canon 500D DSLR attached to the box to take pictures.
We made three separate pinholes: 1mm, 2mm, and 3mm. To take a picture, we covered all but one hole, and set the camera to an appropriate exposure setting. We found that in general in proper sunlight, the 1mm hole worked well with 30 seconds of exposure, 2mm with 20 seconds, and 3mm with 10 seconds. Deviating from these exposure settings seemed to overexpose or underexpose the image. We consistently used F3.5 (the largest aperture available on the DSLR) for all our images. Our experimentation was done mostly with the ISO setting while fixing these parameters.
We found that increasing the ISO led to a lot of redness showing up in our images. The redness was generally also correlated with the amount of light entering since in some instances, even a low ISO combined with a 30-second exposure led to a lot of redness in the image.
The way our screen was set up as a combination of 2 pages, we observed that some of our images looked good on the larger side of the slit created by the two pages, and very reddish on the shorter end of the slit. The reasons for these effects are not clear to us. The reddish effects seemed to disappear when we kept the camera itself in the shade, but picture a very well lit object.
In general, the best images we managed to take were from the 2mm hole and 20 second exposure.
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