[Klaus]

You don't need to be sold, just buy it...  

I don't have a problem with retractable lenses (I only have one, so it would be singular anyway), but I do have one with the magenta / green circled spots round highlights. And this is a very wide angle, so no matter how well it performs - flare resistance is key. If that'd be bad I rather stick with the Sigmas. Although weather sealing and extending tubes are not going too well in my book.

1300 US $ is alright if it's delivering great images.

Hey Klaus, you always wanted light and small lenses. Now you have one, and you still complain. You can still use your funky Laowas 

You may notice that the last review of the Laowa 15 was far from positive (and I gave up on the 10-18).

Regarding the retractable design - I'm having doubts from a mechanical perspective. Based on what I've seen so far such lenses are more prone to centering issues. You may argue that there haven't been any high-end lenses with this mechanism but still ...