While attempting to use the opencv-python interface trying to quickly compare a few algorithms, I installed the opencv3 with python3. Then I did the mistake of googling 'opencv3 python tutorials'. Here I found (but I cannot publish links) But it took me a while before figuring out why SIFT does not work as indicated there. Finally I found a forum post correcting the tutorials on stackoverflow (but I still cannot publish links). After this I got a bit more careful and started to explicitly search for 'python3'.
Now I found that on the official site the links to the python tutorials points to opencv2 tutorials (And again no link... this is silly). Which is good.
What is confusing though that there are a couple of opencv3 python tutorials (see first link), that look quite alike the openvc2 python tutorials, the main difference being that some of the opencv3 tutorials just don't work. Late at night yesterday I thought I came across a forum post saying that opencv3 python tutorials will be discontinued, but unfortunately I cannot find it anymore.
The question being; why are there so many versions of opencv3 python tutorials that were not really updated from opencv2 to opencv3?