This was such a relaxing slice of life video intermixed with the lens details. Hope your cousin was happy with the portrait shots - those were some beautiful shots!
The equivalent of a 65mm lens on a 6x7 would be around 37mm on a 35mm camera. That’s wide for traditional portraits, although it is nice for more environmental portraits. The 150mm is a fine lens but the camera needs to be well calibrated. There is a little (capped) hole in the back of the camera that can adjust the focus, but it’s a process. If you hit the ideal focal range with the 150mm all of the other lenses will be spot on.
65mm for me is a wonderful "normal lens" for everything super sharp, no distortion to worry about, the 150 is an exceptionally sharp lens and comes into its own when you want that tighter shot without loosing the full 6x7 film format, (no cropping) the 50 is a good wide angle, but with some minor distortion, and the 43mm is off the wall wide, very sharp, and with the typical distortion. The 65 and 150 can be used without finder attachments and make for fast framing/focusing, once you get used to them. The lens that surprised me the most is the 210mm F8, if you make the effort to learn how Mamiya designed it be used, you can get some really amazing shots with the 210. Nice video.
I enjoy your videos, I'm interested in photography. The topics you cover are a little obscure, I particularly enjoyed your recreation of the camera used in the film Rear Window. However one suggestion I have is that you could supplement whatever else you do with voiceovers for other videos or commercials or whatever requires the use of a mellifluous tone of voice.
65mm is still a relatively long lens even if it's got a wider field of view on 67-- I thought the 65 had great character, so I'm not sure with all the compromises the 150 has on a rangefinder, that I'd reach for it too often. Another great video