5:1? That is wild! I didn't know about that one, but they do also have a 100mm 2:1 for $450, which is surprisingly affordable - less new than I paid for my used 105.
Granted I might still (eventually...) go with a TC-20 E III since it's only 10% more and I can also use it with my birding lens, but absent that constraint, I'd definitely be thinking hard about that Laowa 100mm.
edit: Well, I can use a 2x TC with my birding lens if I don't mind losing autofocus, anyway - the ones fast enough to AF with it all cost as much as a car...
Granted I might still (eventually...) go with a TC-20 E III since it's only 10% more and I can also use it with my birding lens, but absent that constraint, I'd definitely be thinking hard about that Laowa 100mm.
edit: Well, I can use a 2x TC with my birding lens if I don't mind losing autofocus, anyway - the ones fast enough to AF with it all cost as much as a car...