M42 lenses on a Nikon F body.... with infinity focus

[michr]

Yes although it's not the lens maker formula you are using. Use the Gaussian equation for a thin lens which maps the object distance, z, to image distance, z'.

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Btw I recommend a Field Guide to Geometric Optics by John Grievenkamp...my copy is from when I took his geometric optics course. Handy for looking up fundamental optical calculations.

Thanks for the clarification on the equation and the suggestion of reading material.