He is a guy that does actually know a lot of real facts about optics, his command of English isn't the best maybe, but, he gets his points across in an understandable fashion, and sorts out a lot of the clutter. He's on a lot of forums and has a website with a blog, and actually tests stuff and says what is or isn't good or useful about stuff. worth a listen;
https://www.everydaymarksman.co/podc...HWa4au0gCLvQ6Q