the lens + (L39->M42) + (M42->M42 17~25mm helicoid) + (M42->μ4/3 17~23mm helicoid) + (μ4/3->E)
With this combination you can focus from infinity to ~0.4m, which is quite usable. By defaults these
EL-Nikkor lenses are all APOchromatic ones, the wavelength from 380nm to 700nm is corrected.