12 mm are quite a challenge at times. I really should consider buying the Laowa 7.5 mm rectilinear lens. That’s 15 mm eq, with good optical quality, and it comes with just 170 g. By the way, they also have a 9 mm “Zero-D” lens for APS-C. If I had a Sony, that’s what I’d buy for going light. 210 g for 13.5 mm eq!
On the other hand, I haven’t used anything but the OM-D E-M1 mk iii and the 12-100/4 in a long time 😃