Laowa 35mm F2.8 macro lens will be released in about a week

1 hour ago, dentrock said:

I estimated an EP of 45 at 1:4 focus for the Sony 50 macro.

I haven't used the 180 with it because it's too clumsy for me for close-ups, but an extension of approx 40mm (or just the 35 adapter) should get you close with this lens and that port. The OC for the port on its own is approx 25mm behind the mounting flange.

Many thanks once again!