Reverse Engineering Project

        The first step when you take a picture is to look through the viewfinder and make sure that your desired subject of the photo is in frame. The viewfinder is made up of two rectangular shaped lenses. The smaller lens, the one you put up next to your eye, is a converging lens. The larger one is placed in front of the smaller one, closer to the subject. The purpose of having two lenses is because the first one will show the subject upside down, but the second one will flip it back to rightside up so you, the photographer, see the image as it will be captured.

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        Then you must wind the gear. This action gets the film into position. The gear attaches to the top of a container that has a cylindrical plastic part on the inside, which rotates and rolls in the film, which is initially stored in another cylindrical area on the other side of the camera. The film rolls from left to right, so when you turn the gear, you are in turn pulling the film into the designated area underneath the gear.

        When the gear is wound, the levers and metal spring that are directly adjacent to it rotate until they click into place. These levers in turn rotate the cam, which is a cylindrical peg that attaches to the white gear that is visible on the outside of the camera. The gear indicates how many pictures you have left as well. Once the gear stops moving (indicating that the levers have clicked into place), press the button on the right side of the camera to take the picture. At this point the levers will disengage and push another lever that rotates the shutter outward so that light can enter the lens.

        When the button is pressed to take a picture, the shutter opens up. This allows light to enter through the lens, and these light rays are projected onto the film, which is coated with light-sensitive gelatin emulsion that contains microscopic silver halide crystals.The light rays create an upside-down image on the film. An exposure, created by the lens, produces a slight chemical change in the crystals, and the latent image that is produced is later developed in a lab through a chemical process.

        The flash is released when the capacitor is discharged. The battery is able to charge the capacitor after the button on the camera is pressed, because this button pushes together two flexible metal rods that are attached to a circuit board, closing the circuit and allowing charges to flow which then allows electrons to flow from the battery to the capacitor. When the capacitor is discharged all that electrical energy quickly flows into making the camera flash with a burst of light. A capacitor has two metal plates that both start out electrically neutral. There is a dielectric (an insulator) between the two metal plates that prevents the capacitor from spontaneously discharging. This dielectric can be air, paper, or glass  The battery runs electrical energy through a circuit to the capacitor. Electrons flow to one of the metal plates of a capacitor and develops a net negative charge which repels electrons from the metal plate on the opposite side giving the second metal plate a net positive charge. Eventually, the capacitor is fully charged and has the same voltage as the battery. When the button on a camera is pressed the capacitor is discharged, meaning that electrons on the metal plate with a net negative charge move to the plate with the net positive charge and eventually through the circuit until the capacitor again has a voltage of 0. This sudden "burst" of electrical energy created by this discharge is what powers the flash in a camera. The capacitance of capacitor can be calculated by dividing the charge by the voltage.