Douglas WeissPHY 690Masters ProjectCheap and Easy to Use Pinhole Camera.IntroductionPinhole photography and pinhole cameras are themselves relatively cheap and easy to construct. There is a movement in the artistic community that utilizes this photography format for its unique range of depth and artistic control and freedom that this camera type provides. Even digital pinhole cameras are becoming an artistic craze. These cameras are equally attractive to Physics teachers who favor a demonstration and model based approach their curriculum. Both in Physics education and the artistic community pinhole photography has maintained a core underground following, and is starting to surge in popularity. It is for the same reasons that some in the art community are drawn towards pinhole photography that, also are people in education. Pinhole cameras have relevant physics applications, in particular optics. Many of the principles within optics that are usually demonstrated with diagrams, can be illustrated in a hands-on manor through pinhole photography. Students can work through calculations, derive equations, or observe optics phenomenon through these cameras.Teaching Physics is quickly evolving into a field of modeled lessons and hands-on/involved interaction with the concepts. This being the case, there is an expansion in interest into developing cheap and easy ways to bring physics into the classroom. I contend that Pinhole cameras are so useful in this arena, that much of an optics unit can be demonstrated through the cameras use. Simple right through to the most complex topics can be demonstrated using the camera. These applications are explored further in the “Physics Applications” section.Since a pinhole camera is a fairly simple gadget to assemble, modifying it is equally as easy. This ease of modification opens the door for the cameras to be used for multiple concepts throughout an optics unit. It provides a hands-on experience for students and sets up more than one opportunity for students to predict, test and discuss physics concepts. This avenue for discourse is quite valuable in engaging more students in the class. The mathematics of the pinhole cameras is a fairly easy quantitative experience for high school physics students. The equations are not mind-bending and there is opportunity for them to test relationships within these equations, as well as, rearrange variables to solve for different situations.PurposeThe purpose of this project is to find a cheap and easy way to build such a camera with the focus on its relevance to physics being the primary function. Artistic images and functionality are secondary considerations. This camera design is made to have the functionality and price range of a physics-teaching tool. For this reason material selectionwill have a first priority of cost effectiveness while meeting minimum picture quality standards. It is also important to keep in mind, especially when selecting a container for the camera body, that the materials must be easy to obtain in moderate quantities, as the cameras will be a similar size and provide comparable results. Ease of construction is key to keeping the students focused on the physics at hand (if they are assembling their own). If the camera is for a teacher demo with student predictions and discourse then ease of construction allows the teacher more time for planning a line of questions. Also, the camera should also be easy to modify throughout an optics unit to carry out different functions. Since the cost is low-especially when taking out the cost of consumables-these cameras virtually cost just the time put into assembly and as a result they are very easy to change and throwaway at the end of the year.Physics of the Pinhole CameraPinhole photography is a standard application of many concepts within physics and specifically optics. Concepts such as light travels in straight lines to aperture interference can be illustrated. There is also physics involved in the set up and construction of the actual pinhole camera. There are several dimensions that can be varied for different effects and images. Focal Length and ApertureThe dimensions of both of these aspects of the camera are directly related to each other. There are variations of some of these equations, for this reason I will initiate consensus and use the forms of the equations that I have come across most frequently. Allof the following produce good results and there doesn’t seem to be an agreement on “the”equation to use. For the case of all examples I will use two sample lengths one for an “in classroom” application and one for a longer time period and an “outdoors” focal length. Both camera focal lengths have their strengths in physics and optics applications. These will be discussed in the “Physics Applications” section.The fact that there are many equations for aperture diameter requires a choice to be made. I included a excel chart with sample calculations for each equations, however, for the purpose of the sample camera I am going to go with the equation that seems to be the most modern, or “in-use” today.The size of the aperture based on a desired focal length can be found by the following equation:Da= Fl / 750To determine a focal length based on the diameter of the aperture the equation rearranges to:Fl = Da2 x 750Where Da stands for diameter of aperture and Fl for focal length.If the activity or purpose for which you are making the camera requires a fixed aperture diameter, then the focal length must be calculated and the back of the camera chamber must be shortened by a false back.* Be sure to convert shoebox dimensions in inches to millimeters when calculating aperture diameter.General ConstructionPinhole cameras are simple in their make up. There is only a need for several decisions to be made that affect the dimensions of your camera. The basic structure components are a box, a hole that allows light to enter the camera, and that medium for capturing the image. The medium for capturing an image is a significant part of the cost of a pinhole camera. This is, of course, a reoccurring cost and therefore careful consideration needs to be given to select the best combination of cost with product functionality and ease of use.For both cost, and ease of use, film paper seems to be the best fit. It is easily the cheapest route to go for film. Film paper comes in individual sheets that each captures one image. There
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