Or Urotsukidōji from the late 80s.
I don’t know about the 1900’s, but I’ve seen some 70’s stuff and it was radically different. No weird contortions at unnatural angles to show the penetration, so it was mostly a hairy guy on top of a girl, and at best you could see some extremely furry movement where their genitals should be. And then some close-ups obviously filmed at another time, often with other people.
Also, some 1970’s movies spent more time with the plot than with the sex scenes. Boggles the mind.
It’s interesting to see someone write this. I shan’t provide citations since I don’t want to foul my search history at work any further than it already is, but the complaint I’ve been hearing from folks in the porn business is that the production value has been tracking steadily downward. Since most porn consumers get their content online for free or for nominal prices, the money that used to be generated by DVD sales (or VHS, or theater admissions if you really want to go back) just isn’t there any more, so ambitious, well-produced products are becoming extinct. I’ve heard female performers–even ostensibly well-known folks–who claim that they make more money webcamming than they do in proper shoots. The market for really ambitious projects is almost gone.
Then again, if you take a more democratic view, the cost to enter the market is much lower now than it was 20-30 years ago, so there is a boom in total amount and variety of porn produced, even if the production value is minimal. Want a clip of a voluptuous woman masturbating with a glass dildo? No problem - there’s an index for that. Want to see a slender woman have sex with a man on the beach? There might be a whole site devoted to that now. Likewise, as you point out, many porn consumers never did give a damn about production values to begin with, and many of the “finished” aspects of porn (including that godawful music) are better off gone. It’s not “better in every way”, obviously (what you call “naturalistic” acting is probably more just dispensing with acting altogether–much “amateur” porn kind of boils down to filming a hookup, albeit one staged to show selected acts and pander to a selected audience), but it might be better for most.