Has this to do with Distortion, Zoom, Crop, number of pictures,...?

Dear Pano-Gurus,

I’m a total newbie to panorama photos and already watched a few hours of youtube-tutorials and gathered the appropriate used equipment.

My equipment
- Canon 200D (orUS name rebel SL2)
- Kit Lense (18-50) and a Sigma 8 mm F3,5 EX DG
- Nodal Ninja 3 + RD 10
- Photoshop
- Ptgui and krpano (haven’t bought yet)

So far the basics. What I can’t grasped right now or where and how to put my brain to it, is the distortion in the pano picture and how to reduce it and make it more pleasant to look at. I think I’ve got a clue that it has to do something with the zoom factor of the pano picture and the number of pictures to achieve a sharp level at such zoom factor. Or is this called the crop factor?

Here are two examples that I find are just awesome to look at in terms of distortion.
https://krpano.com/krpano.html?pa…/obertauern.xml
http://www.visio360.de/360-grad-bilde…interaktiv.html

And this is an example where the distortion is just extreme (if you stay at the pre set zoom level)
https://krpano.com/krpano.html?pano=panos/wii/wii.xml

So my question is: How do I get a result like the first two posted examples above: which lens should I use? How many pictures should I take? Where should I focus on first and also after while working with ptgui,...
Hope I could describe it well and clear what I want to achieve.

Love to get some good advice and get better.

P.S.: I just noticed that I've probably posted this in the wrong section, should be under "Talk" right?

Hi Liuduks, thx for the quick answer and also code snippet. Should I take more pictures to get such a sharp result? AND/OR put lot of work into straighten out the picture? Because in the second example all the lines and such seem to be very straight for example.