How come there's still no macro extension rings (with full electric wiring) nor teleconverters for our cameras ? I wouldn't mind one for the 20/1.7 mm: a spare 40/3.5 in the jean's zippo pocket could be handy. I remember, when a rookie photographer, having to shoot a still in studio. Having nothing better at hand, I put a no-brand (or was it Kenko?) 2X converter (and boy! were they bad in the 70's!) behind my Nikkor 2.8/45 GN (yup, the original auto-flashbulb pancake), closed down two stops, i.e. effective f/11, it turned out good enough for a sharp two-page spread.