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Beam source: $10 laser pointer by "Lazerpro".
The batteries ran out the first day so after that it was connected
to a variable power supply set at 4.5v. The beam is first dimmed using Neutral Density (ND) filters, because initially it was over-saturating the camera. I usually used an OD (Optical Density) value of around 3.5 to get a bright image; this is a surprisingly high value, but using less would oversaturate the image in some places. The beam is then expanded using a concave lens. This makes it look like the light is expanding from a point source located at the focal distance of this lens (closer to the laser, see diagram). The collimating lens is placed at it's focal distance away from the point source. So the distance between the lenses is the focal length of the collimating lens minus the focal length of the expanding lens. Part of the beam was weak, so I used an aperture to block some of the dim area. The test section was a small plastic bottle with flat sides. To figure out where to place it, I moved a test pattern slowly towards the camera until it came into focus (this is the zero point). Theoretically it could be placed anywhere between the collimating lens and the camera, but moving it as close as possible to the camera reduces losses. Ideally I would have taken the lens off of the camera and just had the light impact the CCD chip directly; however since that was not possible with the Fujifilm Finepix, I added another lens directly in front to counter-act the effect of the camera lens. It was impossible to know the exact location of the chip or the lens in the camera, so this was an approximation. The lens system has an identical effect to moving the CCD chip to the 'zero point' mentioned above (without a lens system, the zero point would be the CCD chip itself). To determine the actual pixel size and magnification I took images of a target section (see Pixel Size Calculation). Click Here to see pictures of the setup (minus the camera, which I removed and used to take these photos!).
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