Slow motion in porn came about in about 1999 or some time round that year.
If you want my opinion of it. I hate it. That along with a black and white picture have no place in porn.
It may be okay for some crap arty mainstream film, but in porn it should be banned.
Being a big fan of lesbian porn, I have seen many scenes and pairings ruined by slow motion. I had always longed for a meeting between Keri Windsor and Temptress. This is going back about 10 years. It came about but my hopes were dashed when the entire scene was in slow motion but also diced up into repeated segments. WTF. The whole scene ruined. I could have kicked the TV.
That was the only opportunity I had to see them together.
There's been loads more scenes ruined since then, too numerous to mention, but I see these days SM and B/W are not used much.
Just thought I'd air my opinion made on this subject.