[progbits]

https://github.com/jyjblrd/wigglegramLens

This is one option, trading ease of use and low cost for lower picture quality and less light.

[zimpenfish]

Ah, might have to try that. I've been getting adverts for "proper" versions of these (eg the Dispo Parallax) but no-one seems to sells them in a M4/3 mount (and I'm not keen on using adapters.)