High Falls, Pigeon River

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When stacking one lens on another for macro shots (often a normal or wide angle on a telephoto ), what determines the maximum reproduction ratio that the combination can do?

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1 Answer 1

M = Fp / Fr


  • M = magnification
  • Fp = Focal length of the prime lens
  • Fr = Focal length of the reversed lens

Source: Peter Forsell's great page about Math for macro photographers.

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Thanks for the formatting mattdm. –  asalamon74 Jan 4 '13 at 13:36

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