"The Eschlebox" (CS 194-26 Fall 2018 - Project 2)

IVAN JAYAPURNA - CS194-26-ABT, JACKY LU - CS194-26-AFX, SHARABESH RAMESH - CS194-26-AEB



Overview

The goal of this project was to build a pinhole camera out of a cardboard box, coloured paper and duct tape. Using this pinhole camera we took several pictures with varying pinhole sizes in varying locations, comparing the output images to find the optimal configuration. This project was incredibly fun, several key camera concepts including exposure time, ISO, fundamental properties of light were cemented, and cool images were taken. All images can be found in our final image gallery and bells and whistles sections.

Section I: Camera Design

Our camera named "Eschlebox" was mostly designed using recycled waste and borrowed / scrounged resources from Eschleman Hall (all our images were taken here there as well!). The main box is an Amazon package box, insides lined with black paper other than the white screen at the back - a white sheet of paper. Black sheets were fixed with black duct tape, white sheets with clear tape behind the sheet. We chose the long orientation for our box with our DSLR camera's minimum focal length (of roughly 1-1.5feet) in mind. Admittedly, the lack of box width did cause issues later on, however, overall I believe the design choice tradeoff yielded sharper images and thus was worth it. All possible sources of light leakage into the box were covered by duct tape or black paper, such that the pinhole is the only light source. The pinhole itself is a set of 3 removable sheets of thinner cardboard wrapped in duct tape, with holes made using an actual pin of 1mm, 3mm and 5mm. These are removable and swappable onto the box, slotting over and covering up a much larger hole on the box itself.

We additionally included a mini support stand for the digital camera for image stability, and to completely ensure no leakage of light, we threw a jacket over the top of the camera to prevent light from entering in from the gaps between the camera lens and cardboard box. Images of the camera setup and in action can be seen below.

setup with digital camera and stand visible
pinhole camera in action!

Section II: Pinhole Size Comparison

We calculated using the equation given and the length of our box, the theoretical ideal aperture size for our pinhole to be 0.89mm in diameter. With the limited availability of crude cutting tools we rounded this up to 1mm, giving 3 aperture diameters of 1mm, 3mm and 5mm tested. Images comparing the results of these 3 aperture sizes can be seen below (note that images have been cropped):



5mm hole, 15s exposure, 640 ISO
3mm hole, 15s exposure, 640 ISO
1mm hole, 30s exposure, 640 ISO
5mm hole, 30s exposure, 2000 ISO
3mm hole, 30s exposure, 2000 ISO
1mm hole, 30s exposure, 2000 ISO
5mm hole, 15s exposure, 640 ISO
3mm hole, 20s exposure, 640 ISO
1mm hole, 20s exposure, 640 ISO

From looking at the images above, as well as our experience with failed experimenting, there are 3 clear takeaway conclusions: 1.) The smaller the pinhole the sharper the image, 2.) The smaller the pinhole the darker the image, 3.) The size of the pinhole is often less significant than the image capture settings on the DSLR camera (focus, ISO, exposure time)

1.) It makes physical sense that a smaller pinhole size will yield a sharper image, as there is less light coming in from less angles, as such they will focus more accurately on the same spot on the screen, yielding a sharper image on the screen. An in-focus DSLR camera will thus capture a sharper final image. Thus in an ideal world the 1mm pinhole should always be used to yield the "best" image (unfortunately we can see that this is not the case)

2.) This is because a smaller pinhole size will also yield a darker image, as less light in general will enter the box - there is a darkness-sharpness tradeoff with using the pinhole camera on its own.

3.) A solution to counter the darkness issue on the smaller pinhole images, we simply either raised exposure time, ISO, or both on our DSLR camera. This however, would not be possible on a pure pinhole camera. Thus, our group found that by messing with these camera settings, we could get decently / equivalently high quality photos on both the 3mm and 1mm pinholes, making the actual aperture size of the hole almost secondary.

Ultimately, our conclusion on what size of pinhole to use without crazy high iso or exposure time, is to use the 1mm pinhole for very bright setting (i.e. outdoors), and to use the 3mm pinhole for darker and indoor settings - as otherwise there will not be enough light for a good image.

Section III: Final Image Gallery

Finally, with the optimal settings somewhat fine tuned to be for outdoor photos: 1mm pinhole size, 15s exposure time, and roughy 640 ISO, and for indoor photos: 3mm pinhole size, 30s exposure time, and roughly 2000 ISO, the following photos below were taken for our final gallery (Note that all images were manually cropped to remove black borders from the box). Enjoy!



Eschleman Roof View of Campus
Eschleman 3rd Floor Hallway
Eschleman View of Bancroft
Eschleman 3rd Floor Inner Hallway
Eschleman View of Lower Sproul
Selfie in Eschleman

Section IV: Bells and Whistles

Here are some cool extra credit images we attempted! Light painting in a dark room worked out amazingly well using the 5mm aperture diameter. We also tried our own creative idea, using a 1.5 minute long exposure with light tricks to clone Jacky's face 3 times, and it sort of worked (just super dark).


Light Painting 1 "BOX"
Light Painting 1 "MAN"
Light Painting 3 "WOW"
Light Painting 4 "Lit Jacky"
Jacky x3