[photonius]

I like the concept very much. I'm actually surprised nobody came up with a similar solution already:

https://www.kickstarter.com/projects/revoring/revoring-a-variable-step-ring-for-your-camera-lens-filters

Looks interesting, but the mechanism sure must take some space. I'm wondering about the vignetting. Curious how it will work in real life, looks like one has to buy filters again, since it's part of the filter, or not?.