M49 Reverse Ring

prusaprinters

<p>Reverse ring for macro photography with two lenses with M49 filter threads.</p><p>With a reverse ring, you can <a href="https://en.wikipedia.org/wiki/Macro_photography#/media/File:RevLensMac.png">mount a camera lens in front of another lens in reverse (filter thread to filter thread) to create a macro lens</a>. The close-up photo of the printed ring was taken using this technique, with a Helios 44-2 lens mounted in reverse on a Jupiter 9 lens.</p><p>The threads are designed to M49 x 0.75 mm specification. You will probably need to scale X and Y axis down a bit for it to fit, depending on your printer, material, layer height and slicer. I am using 99.93% scaling factor for PLA with 0.05 mm layers on Prusa MINI+. With lower layer height, the threads seem to work smoother, although it works even with 0.2 mm layers. I recommend printing this with no infill, perimeters only (just set the number of perimeters high enough, 10 will definitely work).</p><p>If you tighten the ring too much and cannot easily unscrew it, use the slots on the sides with a spanner wrench or (carefully) just one of them with a small screwdriver.</p><p>I will publish a parametric file for creating different filter thread sizes when I get to it. Meanwhile, if you need a different size of filter thread, send me a message and I will create and upload it.</p>