I thought this an interesting look inside the SL lens...

https://www.lensrentals.com/blog/201...mm-f2-8-4-asph

I wasn't too thrilled with the implied snark/disparagement of Leica/Leica users in his first paragraph, but didn't let it detract from the nice glimpse inside the SL lens. It seems a nicely designed, solidly constructed piece that will last a long time.

G