By Scott Sparrold
If you are like me, then you crave a deep understanding of how optics works. This nomograph beautifully shows how the lens makers equation works, by giving a cartesian coordinate system for the conjugates and another axis for the focal length. A load line shows their interactions.
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Homework: - The total track, or the object to image distance, is 139 mm. What is the focal length required to have a 2x magnification? Where is the lens located relative to the object? (Magnification hint: the image distance is twice the object distance)
- A virtual object is 30 mm inside a negative lens of focal length -100 mm. Where is the image?
- Your new boss tells you to go into a lab and “focus a lens” for unity magnification. Upon entering there is an optical rail with three components: An illuminated pinhole, a lens and a camera. After moving this stuff around to get mag = 1.0, you find the pinhole is 43.7 mm from the lens. What is the focal length of the lens? What is the distance from the lens to the camera?
- Upon completing problem #3 above your new boss comes in and shows you that you lens is a liquid lens that is capable of changing focal lengths (opto-tune Edmund Optics part # 83918. He changes the focal length to what he claims is 80 mm. After refocusing the camera, what is the lens to camera distance?
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