I am currently struggling with some lens equations. I hope this is the right place to ask such questions.

What I'm trying to accomplish is to add a separate single lens to a camera setup and calculate the new focus plane (See the added image).

Camera setup with added lens.

To calculate the new focus plane I am assuming the 16 mm Kowa lens (on the camera) to behave like a thin 16 mm lens. Using simple lens equations, I then calculate how adding the separate lens would shift the focal plane.

However, the results I get from these calculations do not correspond to what I see in my experimental setup.

What am I doing wrong? Does substituting the Kowa lens for a thin 16 mm lens in my calculations make that much of a difference? If so, how could I calculate this without knowing exactly what is inside of the Kowa lens?

Writing out my calculations here would make this a wall of text, so I left them out. If they are required though, I would be happy to add them.

  • $\begingroup$ I'm not familiar with this specific lens but you should be able to substitute the whole KOWA lens assembly with some equivalent optics. Depending on the KOWA internals this could be a thin lens with a specific focal distance. $\endgroup$ – user883521 Aug 4 '19 at 16:32
  • $\begingroup$ What calculations did you do exactly and how do these compare to your experiment? Did you measure multiple configurations? $\endgroup$ – user883521 Aug 4 '19 at 16:33

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