This feels like it should be obvious, but I'm failing to figure it out.
I own a Sony a5100 -- an APS-C camera with a 1.6 crop factor.
I have long owned the SEL50F18, a 50mm f/1.8 lens designed for APS-C.
I wanted a slightly-more-telephoto lens to add to my kit, and after having tons of fun reading reviews, I decided to buy an old manual Minolta MC ROKKOR-PG 50mm f/1.4 and an adapter to E-mount. It was cheap (about $75 for the set), and the idea of a fully-manual lens with some "character" sounded like fun.
Since the Minolta MC was for a 35mm film SLR, I anticipated the 1.6 crop factor making this lens have the same angle-of-view as an 80mm lens designed for APS-C (since the 50mm lens should produce an image circle much larger than my APS-C sensor)
The adapter is a cheap "Fotasy MD-NEX" adapter which has no optical elements.
So, I was very surprised when my gear arrived today and the new ROKKOR-PG produces images that have the same angle of view (or, at least, close enough that I can't tell the difference)
Where is the hole in my logic? Why do these two lenses produce images with similar angle-of-view?