Will this combination give me 1:1 macro?

[lenspeeper]

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I am considering a macro lens for my Leica TL2. The L mount Macro is 60mm and while yielding 1:1 macro, the focus distance to an animate subject is really too close to be useful.It would tend to make the little critters a bit jumpy. There are other alternatives such as a FF 100mm or 105mm Nikon F mount Tokina or Nikkor with a NIK to L mount lens adapter.

So, I am considering a used Leica Macro-Elmar R 100mm lens which, with the macro adapter, results in a 1:1.6 image with a full frame 35mm Leica R camera. So, it seems to me that this lens combination ( lens + Leica R macro adapter) used with an R to L mount lens adapter should yield an image closer to !:1 macro when taking into account the 1.5 sensor ratio between FFG and APSC.

The area of a FF sensor or negative is 864 square mm (36mm x 24mm). The area of an APSC sensor is 357.87 square. So an APSC sensor has .415 the area of a FF sensor. Or inversely, the ratio of the FF area/ TheAPSC area is 2.41. So the area of the APSC is close to one half.

The Macro-Elmar 100mm with macro adapter yields a reproduction ratio of 1:1.6 on a FF sensor. So doesn't it make sense that a FF Macro lens with a reproduction ratio of 1:1:6 would yield an effective reproduction ratio on an APSC sensor of 1: 114 or very close to 1:1?

Think about it and let me know your thoughts.

Am I thinking straight, or should I reconsider?

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[mmradman]

On full frame camera, 100mm lens, for example, is exactly that 100mm lens. Image magnification is function of the closest focusing distance.  Closest focus distance is dependent on lens optical design and construction.

When you fit above 100mm lens to APS-C camera you get effectively 150mm lens.  It would have identical close focus distance but magnification would increase as it is lens with "bigger focal" length.  Actually FL is constant but image is projected onto a smaller area and that is equivalent of having longer lens on full frame. Works with smaller or bigger sensors, only limitation on bigger sensors is projected image circle.